Light emitting device and method for manufacturing light emitting device

ABSTRACT

A light emitting device ( 100 ) includes a base member ( 101 ), electrically conductive members ( 102   a,    102   b ) disposed on the base member ( 101 ), a light emitting element ( 104 ) mounted on the electrically conductive members ( 102   a,    102   b ), an insulating filler ( 114 ) covering at least a portion of surfaces of the electrically conductive members ( 102   a,    102   b ) where the light emitting element ( 104 ) is not mounted, and a light transmissive member ( 108 ) covering the light emitting element ( 104 ).

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.14/884,718, filed Oct. 15, 2015, which is a continuation of U.S. patentapplication Ser. No. 13/577,491, filed Oct. 29, 2012, now U.S. Pat. No.9,196,805, which is a National Stage Entry of PCT/JP2011/051742, filedJan. 28, 2011, which claims priority from Japanese Patent ApplicationNo. 2010-026607, filed Feb. 9, 2010; from Japanese Patent ApplicationNo. 2010-044771, filed Mar. 1, 2010; from Japanese Patent ApplicationNo. 2010-159434, filed Jul. 14, 2010; and from Japanese PatentApplication No. 2010-186504, filed Aug. 23, 2010. The contents of eachof the above-referenced applications are hereby incorporated byreference in their entireties.

BACKGROUND OF THE INVENTION Technical Field

The present invention relates to a light emitting device applicable topurposes such as an indicator, a lighting apparatus, a display, abacklight light source for liquid crystal display, and a method ofmanufacturing the light emitting device.

Description of Background Art

In recent years, various semiconductor devices have been proposed andare put in practical use, and the demand for high performance is everincreasing. In particular, electric components are required to have highreliability to maintain performance for a long period of time, in otherwords, to maintain stable operation for a long period of time, evenunder severe environment. The same applies for light emitting diodes(LEDs) and other light emitting devices. Requirements for higherperformance in the area of general lighting, in-vehicle lighting, andthe like, is growing daily, and further higher output (higher luminance)and higher reliability are demanded. A further demand is to supply sucha device at a low price while fulfilling those requirements.

In order to achieve higher output power, it is efficient to improveoptical output efficiency of the light emitting element (semiconductorlight emitting element) which is to be used. For a method to improve theoptical output power of the light emitting element, for example, amethod using a small chip dice (light emitting element) is employed (forexample, see Patent Literature 1). Particularly, in the case where agallium nitride-based LED is used for the light emitting element, thelight emitted from the light emitting element propagates in thesemiconductor layer, and therefore is absorbed when it is reflected atthe electrode or the like (for example, see Patent Literature 2). Forthis reason, the dice is made as a small chip to allow the emitted lightto be extracted to outside. Thus, absorbtion loss of light can bedecreased. In the case where a small chip dice is used, a limited amountof electric current is allowed to flow through. Thus, employing amulti-dice structure having a plurality of small chips enables to obtaina desired optical output efficiently.

In addition, for a structure of the light emitting element, a flip-chiptype may be employed in which the electrode surface to be electricallyconnected to an external electrode is arranged downward (hereinafter maybe referred to as a face-down element or FD element). (see PatentLiteratures 1, 3). This structure does not have an electrode and/or wireetc., on the principal light extracting surface of the light emittedfrom the light emitting element. Thus, it is said to be able to furtherimprove the optical output efficiency (extracting efficiency).

Also, in order to improve the optical output power of the light emittingelement, a silver plating which has a high reflectance is typicallyapplied on the electrically conductive member used for the base member.On the other hand, as the material of the base member, in the fields ofgeneral lighting, in-vehicle lighting, and back light source, ceramicmaterials which are resistant to deterioration under high temperatureand high optical density are typically used (for example, see PatentLiterature 1).

Further, gold (Au) is typically used as a conductive wire used for aprotective element or a face-up element (hereinafter may be referred toas a FU element) having an electrode surface arranged over the lightemitting element. Au wire is very soft and a ball bonding technique canbe used, so that very thin wires of ●100 μm or less, for example(diameter) of several tens of micrometers can be used. Thus, in the casewhere a plurality of light emitting elements are mounted, a plurality ofconductive wires can be used.

Typically, a light emitting device has a base member (a package, i.e. amount substrate having a wiring pattern etc.) on which electricalcomponents such as a light emitting element and a protective element aremounted, and electrically conductive members which supply electriccurrent (electric power) to such electric components. The light emittingdevice further has a sealing member protecting the electric componentsfrom external environment. However, loss due to absorption of light(absorption loss of light) occurs depending on the materials of the basemember, electrically conductive members, sealing member, etc.Particularly, the surface area of the electrically conductive members isrelatively large, absorption loss of light by the electricallyconductive members may reduce light extraction efficiency. For higheroutput power, the light extraction efficiency to be improved, and forthis, improvement in the optical output efficiency of the light emittingelement (semiconductor light emitting element), and also reduction ofabsorption loss of light by the materials of base member (including thepackage), electrically conductive members, and sealing member areeffective.

In order to improve the light extracting efficiency, for example,application of a plating of a metal member having high reflectance onthe inner surface of the package to suppress absorption of light by thebase member and to efficiently extract light to the outside is proposed(see Patent Literature 4).

Disposing of a member having high reflectance in the light emittingdevice is viewed as a way to suppress optical absorption by the membersused in the light emitting device, but among those materials having highreflectance (such as silver), some materials are subjected tosulfuration or halogenation and may cause long term reliabilityconcerns. That is, there has been a problem in which, discoloration dueto sulfuration or halogenation of the material by the sulfur componentetc., contained in the atmosphere causes reduction of the reflectance ofthe material, which results in reduction of the light extractingefficiency.

In order to solve such a problem, Patent Literature 5 discloses formingof titanium dioxide (TiO₂) etc., as a protective film on the surface ofa metal reflection film by using sputtering or vapor deposition toimprove its gas barrier property. Also, Patent Literature 6 discloses areduction of the problems caused by heat, by a reflector free ofdiscoloration formed by covering the reflecting surface of the reflectorwith a high-reflecting resin layer made of a powder material having highreflectance mixed with a resin, and by employing a material havingexcellent heat dissipating property for the reflector.

Also, known is a light emitting device in which, other than that asdescribed above, a light emitting element is mounted in a flip-chipmounting manner as described in Patent Literature 7. The light emittingelement includes a transparent substrate such as sapphire, and asemiconductor layer stacked thereon. In the light emitting element, eachelectrode is bonded on the lead pattern through a respective conductivebump. With this arrangement, the transparent substrate side of the lightemitting element can be utilized as the light extracting side. Further,a light emitting device in which a lower portion and a side surface arecovered with a resin containing a filler (Patent Literatures 8 to 11),and a technique of electrodeposition of titanium dioxide on the lightemitting element (Patent Literature 12).

Patent Literature 1: JP 2009-135485A

Patent Literature 2: JP 2008-112959A

Patent Literature 3: JP 2005-150484A

Patent Literature 4: JP 2006-156603A

Patent Literature 5: JP 2006-351964A

Patent Literature 6: JP 2007-281260A

Patent Literature 7: JP 2005-210051A

Patent Literature 8: JP 2004-172160A

Patent Literature 9: JP 2007-109948A

Patent Literature 10: JP 2007-19096A

Patent Literature 11: JP 2009-130237A

Patent Literature 12: JP 2004-158843A

DISCLOSURE OF INVENTION Problems to be Solved by the Invention

However, these conventional technologies have problems with regard tolight extraction in light emitting devices as described below. Even thesurface of the metal reflecting film is coated with titanium dioxide(TiO₂) etc., absorption loss of light by such as the base member and theconductive portion occurs depending on the location of the coating, andsufficient improvement in the light extracting efficiency cannot beobtained.

In order to secure the insulation between the positive electrode memberand the negative electrode member, an insulating region (hereinafter maybe referred to as a slit (groove) in conductive portion) of, for exampleabout several hundred microns is needed to be arranged in the lightemitting element mounting surface of the base member and the bottomsurface and its adjacent portion of the dice of FD element, whichresults in exposure of the base member at the insulating region. Leakageof light occurs at the exposed portion (wet portion) and the directionof the leaking light is opposite to the direction of extracting light,resulting in optical loss.

In the case where a material such as Au having a high optical absorptionproperty in the blue region is used for the wires to electricallyconnect the protective element and the light emitting element, a problemmay also arise due to the close proximity of the wires to the lightemitting element, absorption loss of light occurs which results inreduction of the light extracting efficiency. Further, in PatentLiteratures 4 to 6, there is no description of the solution to thoseproblems. Also described is that the highly-reflective resin layerproposed in Patent Literature 6 is a mixture of a resin and a powdermaterial, so that there is a problem in moldability, and there is atendency of a decrease in moldability particularly in the case where agreat amount of the highly-reflective powder material is contained(paragraph [0022] etc).

In Patent Literature 7, light irradiated from the light emitting elementis absorbed by the conductive bumps and leads. Accordingly, reduction ofabsorption of light by the conductive bump and leads to improve thelight extracting efficiency is demanded. In the field of lighting, thedemand for uniform color distribution of the light is increasing.

In the case of applying a reflective member on the light emittingelement, in the transparent substrate and the semiconductor layer whichconstitute the light emitting element, if all of the side surfaces andthe upper surface of the transparent substrate are covered with thelight-reflective member such as TiO₂, the light extraction efficiencydecreases due to the absorption of light by the reflective member. Also,if a resin is applied to coat the electrically conductive member etc.,the resin rises to the side surfaces of the transparent substrate andeventually all of the side surfaces of the transparent substrate arecovered with the resin. When the viscosity of the resin is adjusted soas not to rise up, the content of the light-reflective material isneeded to be increased for a higher viscosity, so that it makesdifficult to cover the entire surfaces of the electrically conductivemembers. Further, in the case where the reflective member is disposed soas not to cover the side surfaces of the semiconductor layer and in thecase where the light transmissive member includes a fluorescentmaterial, the fluorescent material settles and the semiconductor isberried in the fluorescent material. Accordingly, the ratio ofexcitation and emission at the lower portion of the fluorescent materiallayer increases, so that the light is absorbed by the fluorescentmaterial while travelling through the thick layer of the fluorescentmaterial, resulting in a decrease in the light extracting efficiency.

The present invention is devised to solve the problems as describedabove, and is aimed to provide a light emitting device capable ofefficiently extracting light from the light emitting element to outside,and a method of manufacturing the same. Also, the present invention isaimed to provide a light emitting device with high reliability and amethod of manufacturing the same, in which the electrically conductivemembers etc., over the base member is covered with a reflective member,for example, an insulating filler, which enables to suppress thedeterioration of the members which constitute the light emitting deviceand the absorption of light by such members, and a portion of the sidesurfaces and the upper surface of the transparent substrate of the lightemitting element are exposed. Thus, light from the light emittingelement can be extracted to outside efficiently.

Means to Solve the Problems

In order to solve the above problems, a light emitting device accordingto the present invention includes a light emitting element having asemiconductor layer and a transparent substrate, a reflective memberexposing at least a part of side surfaces and a top surface of thetransparent substrate and covering side surfaces of the semiconductorlayer; and a light transmissive member covering a portion of thetransparent substrate exposed from the reflective member.

With such a construction, at least a portion of the side surfaces andthe upper surface of the transparent substrate are exposed, whichenables to suppress the absorption of light by the reflective member andthus enables to prevent the reduction in the light extractingefficiency.

A light emitting device according to the present invention may furtherhave a base member and electrically conductive members disposed on thebase member. The light emitting element is mounted on the electricallyconductive members, and at the surface of the electrically conductivemembers, at least a portion which does not have the light emittingelement mounted thereon is covered with an insulating filler which isthe reflective member, and the light transmissive member covers thelight emitting element. In the specification, the term “a portion whereno light emitting element is mounted” refers to a portion outside of theoutline of light emitting element in the view from the top surface sideof the light emitting device. That is, in the view from the top surfaceside, the portion behind the light emitting element is not necessarilycovered with the insulating filler. But, the portion behind the lightemitting element may be covered with the insulating filler.

According to the construction as described above, the surface of theelectrically conductive members formed on the base member are coveredwith the insulating filler. Thus, the reflection efficiency of light atthe electrically conductive member is improved. Also, the surface of theelectrically conductive members are covered with the insulating filler.Therefore, a specific member having a high reflectance is notnecessarily used for the electrically conductive member and a stablemember resistant to deterioration and corrosion can be employed. Inaddition, the surface of the electrically conductive members are coveredwith the filler, so that even a portion of the electrically conductivemembers become deteriorated or corroded, reduction of the lightextracting efficiency of the light emitting device can be prevented.

A light emitting device according to the present invention may have aconstruction in which, the base member has a recess, the electricallyconductive members are disposed on the bottom surface and the sidesurface of the recess, and the light emitting element is mounted on thebottom surface of the recess. In addition, at the side surfaces of therecess at a portion abutting on the top edge surface of the recesspreferably have a region where an electrically conductive member is notformed, and the side surfaces of the recess at a portion abutting on thebottom surface of the recess preferably have a region where anelectrically conductive member is not formed.

In addition, it is preferable that at the top edge surface side of therecess, the side surfaces of the recess have a step, and a side surfaceof the step has a region where an electrically conductive member is notformed. Further, the shortest distance between a highest surface ofbottom surfaces of the step to a surface of the light transmissivemember is preferably ⅕ or less with respect to the height of the recess,and the surface of the light transmissive member preferably has arecessed shape. In addition, the filler is preferably applied to athickness of 5 μm or greater.

In the light emitting device, the reflectance of the filler ispreferably 50% or greater to light of an emission wavelength. With theconstruction as described above, the light extracting efficiency of thelight emitting device is improved.

It is preferable that in the light emitting device, the filler coversthe surface of the light emitting element, and the surface area of asingle light emitting element which is covered with the filler is lessthan 50% of the entire surface area of the single light emittingelement.

With the construction as described above, the proportion of the emissionfrom the light emitting element which is blocked by the filler is low,so that the decline in the optical output power of the light emittingelement can be prevented.

Further, it is preferable that in the light emitting device, theelectrically conductive members respectively have a positive electrodeand a negative electrode, the electrodes are disposed spaced apart fromeach other on the base member, and the filler is applied covering atleast a portion between the electrodes.

With the construction as described above, the filler is applied to theslit (groove) in the conductive portion created between the electrodes,so that leakage of the light from the bottom of the base member throughthe slit (groove) in the conductive portion can be prevented. With thisarrangement, the light extracting efficiency can be further improved.

The distance between the electrodes, that is the width of the slit(groove) in the electrically conductive portion is preferably 200 μm orless. The width of the slit (groove) in the conductive portion 200 μm orless facilitates covering of the groove portion with the filler.

In the light emitting device, the light emitting element is preferablymounted in flip-chip mounting manner. With the construction as describedabove, a wireless light emitting element can be employed, so thatoptical absorption by the conductive wires can be eliminated and theemission can be extracted efficiently from the light extracting surfaceside. Also, the periphery and the bottom of the light emitting elementwhich is mounted in a flip-chip manner are covered with the filler, sothat light from the light emitting surface side of the light emittingelement can be extracted to outside efficiently.

It is preferable that a protective element is mounted in the lightemitting device and 50% or greater area of the surface of the protectiveelement is covered with the filler. With the construction as describedabove, optical absorption by the protective element can be prevented.

At least a portion of the filler is preferably covered with a lightblocking member. With this arrangement, light from the light emittingelement is reflected by the filler and the light blocking member, sothat the light extracting efficiency can be improved.

The light blocking member preferably covers the side walls of the basemember. With the construction as described above, light from the lightemitting element is reflected by the light blocking member and the lightextracting efficiency can be improved.

The light transmissive member preferably covers the filler in additionto the light emitting element. With the construction as described above,the surface of the filler can be protected.

A light emitting device according to an aspect of the present inventionincludes a base member, electrically conductive members disposed on thebase member, a light emitting element mounted on the electricallyconductive members, a wire electrically connecting each electrodeportion of the electrically conductive members with respective electrodeterminals of the light emitting element, an insulating filler coveringthe electrically conductive portion which does not have the lightemitting element mounted thereon and the lower surface of the wires, anda light transmissive member covering the light emitting element and thefiller.

According to the construction as described above, the lower surface ofthe wires are covered with the filler, so that the amount the lightwhich is emitted from the light emitting element directly on the wiresand absorbed by the wires can be reduced. Particularly, the lowersurfaces of the wires are at positions directly irradiated with thelight from the light emitting element, so that forming of the filler onthe lower surfaces of the wires allows to prevent the absorption of thelight by the wires efficiently.

The gaps among the filler are preferably impregnated with a lighttransmissive member. With the construction as described above, adhesionbetween the filler and the light transmissive member can be improved.The light transmissive member is configured such that light from thelight emitting element transmits through it and is extracted to outside,and also that it seals the light emitting element, thus it may be calleda sealing member. In the case where the light emitting device has alight blocking member, the gaps among the filler are impregnated withthe light blocking member, so that adhesion between the filler and thelight blocking member can be improved.

Further, in the region covered with the filler, the filler is preferablycontained more than 50 volume percent with respect to the volume of theimpregnated light transmissive member.

A light emitting device according to an aspect of the present inventionincludes a light emitting element which has a semiconductor layer and apositive electrode and a negative electrode respectively disposed on therespective surfaces of the semiconductor layer, electrically conductivemembers each bonded to the positive electrode and negative electroderespectively, a reflective member which covers the side surfaces of thepositive electrode and negative electrode and the side surfaces of theelectrically conductive members, and a light transmissive membercovering an upper surface opposite to the respective surfaces having theelectrodes disposed thereon and side surfaces of the light emittingelement.

With the construction as described above, the reflective member isformed around the electrodes of the light emitting element, so that astructure which allows little leakage of light in the downward directioncan be obtained. Thus, optical loss due to the light entering under thelight emitting element can be reduced. Also, the reflective memberreflects light which enters under the light emitting element, so thatthe light extracting efficiency can be improved.

In a light emitting device according to the present invention, thereflective member is preferably exposed at the side surfaces of thelight emitting device. With the structure as described above, theabsorption of the light under the light emitting element can beprevented.

In a light emitting device according to the present invention, theinterface between the light transmissive member and the reflectivemember is located at the side surface side of the light emittingelement. With the construction as described above, light can beextracted from the upper surface and the side surfaces of the lightemitting element.

It is preferable that in a light emitting device according to thepresent invention, the thickness from the upper surface of the lightemitting element to the upper surface of the light transmissive memberis approximately the same as the thickness from a side surface of thelight emitting element to a side surface of the light transmissivemember. With the construction as described above, a preferable opticaldistribution can be obtained in the near-field. On the other hand,forming the thickness from a side surface of the light emitting elementto a side surface of the light transmissive member smaller than thethickness of the upper surface of the light emitting element to theupper surface of the light transmissive member, a preferable opticaldistribution can be obtained in the far-field. Thus, such a constructionmay also be employed.

In the light emitting device according to the present invention, thelight transmissive member preferably contains a wavelength convertingmember. According to the construction as described above, the lightemitting device capable of emitting light having a desired wavelengthcan be obtained. Also, the structure as described above allows selectionof color before disposing on the mounting substrate, so that the yieldratio after mounting the light emitting element is improved.

A method of manufacturing a light emitting device according to thepresent invention includes a step of bonding the electrodes of aplurality of light emitting elements on a support substrate, a step offorming a reflective member at least around the electrodes of the lightemitting elements by using an electrolytic plating technique, anelectrodeposition coating technique, or an electrostatic coatingtechnique.

According to the procedure as described above, a reflective member isformed around the electrodes of the light emitting elements so thatoptical loss due to light propagates downward of the light emittingelements can be reduced. In addition, the reflective member is easilyformed to the electrically conductive portions which are exposed justbefore the step of forming the reflective member.

A method of manufacturing a light emitting device according to thepresent invention includes a step of forming electrically conductivemembers on a base member which is a support substrate, a step ofmounting a light emitting element on the electrically conductive membersby die-bonding, applying an insulating filler, which is a reflectivemember, to cover a portion of a surface of the electrically conductivemembers where the light emitting element is not disposed, by using anelectrolytic plating technique, an electrodeposition technique, or anelectrostatic coating technique, and a step of covering the lightemitting element with a light transmissive member.

According to the method of manufacturing a light emitting device, alight emitting device capable of exerting predetermined effect asdescribed above can be provided.

It is preferable that the base member has a recess, electricallyconductive members are formed on the bottom surface and a side surfaceof the recess, and a light emitting element is mounted on the bottomsurface of the recess. In addition, the filler is preferably applied toa thickness of 5 μm or greater.

It is preferable that after the die-bonding the method further includesa step of wire-bonding of electrically connecting a portion of theconductive member, which serves as an electrode, and an electrodeterminal of the light emitting element by using a wire, and in the stepof applying a filler, the filler is applied to cover a lower portion ofthe wires. Also, a step of covering the filler with a light blockingmember is preferably included.

A method of manufacturing a light emitting device according to anotheraspect of the present invention may include a step of disposing alighttransmissive member on the reflective member to cover a side surface andan upper surface of the light emitting element, and a step of dividingthe light emitting element into individual units which includes removingthe support substrate and dividing the reflective member and lighttransmissive member.

Also, in a method of manufacturing a light emitting device according toan aspect of the present invention, it is preferable that, in the stepof disposing the light transmissive member, the light transmissivemember is impregnated in the reflective member. With the arrangement asdescribed above, the reflective member can be fixed efficiently.

In a method of manufacturing a light emitting device according to anaspect of the present invention, the light transmissive memberpreferably contains a wavelength converting member. With the arrangementdescribed above, at the time of individually separating the lightemitting elements, the thickness of the light transmissive member whichcontains a wavelength-converting member can be adjusted, so that a lightemitting device which have less color unevenness can be obtained.

Effects of the Invention

With the light emitting device according to the present invention,absorption of light due to the conductive portions such as theelectrically conductive member can be suppressed, so that light from thelight emitting element can be extracted efficiently, which allowsobtaining higher output. Further, according to the light emitting deviceaccording to the present invention, leakage of light from the bottomsurface of the base member can be prevented by coating the slit in theconductive portion with the filler, so that light from the lightemitting element can be extracted more efficiently and thus higheroptical output power can be achieved.

In the light emitting device described above, insulating filler capableof reflecting light is applied so that the light extracting efficiencycan be improved without using a specific material which has a highreflectance for the electrically conductive member. Further, theinsulating filler is formed with a greater thickness, so thatdiscoloration and corrosion of the electrically conductive member can besuppressed. With such an arrangement as described above, reliability canbe improved.

Further, with the light emitting device according to the presentinvention, the reflective member is formed around the electrodes of thelight emitting element, so that a structure which allows little leakageof light in the downward direction can be obtained. Thus, optical lossdue to the light entering under the light emitting element can bereduced. Also, the reflective member reflects light which enters underthe light emitting element, so that the light extracting efficiency canbe improved.

According to a method of manufacturing a light emitting device accordingto the present invention, a light emitting device of high optical outputand high reliability can be manufactured. According to a method ofmanufacturing a light emitting device according to the presentinvention, a reflective member is formed around the electrodes of thelight emitting elements so that optical loss due to light propagatesdownward of the light emitting elements can be reduced. Also, thereflective member reflects light which enters under the light emittingelement, so that the light extracting efficiency can be improved.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1(a) is a perspective, part transmissive view of an example of alight emitting device according to a first embodiment of the presentinvention, and FIG. 1(b) is a plan, part transmissive view, viewed fromthe light emitting surface side of the light emitting device shown inFIG. 1(a).

FIG. 2(a) is a cross-sectional view of the light emitting device, takenalong arrow line X2-X2 in FIG. 1(b), and FIG. 2(b) is a schematicdiagram of a light emitting element of the light emitting device shownin FIG. 1.

FIGS. 3(a) and 3(b) are cross sectional views illustrating manufacturingsteps of a light emitting device according to the first embodiment ofthe present invention, and FIGS. 3(a) and 3(b) each corresponds to thecross-sectional view of the light emitting device, taken along arrowline X2-X2 in FIG. 1(b).

FIGS. 4(a) and 4(b) are cross sectional views illustrating manufacturingsteps of a light emitting device according to the first embodiment ofthe present invention. FIG. 4(a) corresponds to the cross-sectional viewof the light emitting device, taken along arrow line X2-X2 in FIG. 1(b)and FIG. 4(b) corresponds to the cross-sectional view of the lightemitting device, taken along arrow line X1-X1 in FIG. 1(b).

FIGS. 5(a) and 5(b) are cross sectional views illustrating manufacturingsteps of a light emitting device according to the first embodiment ofthe present invention. FIG. 5(a) corresponds to the cross-sectional viewof the light emitting device, taken along arrow line X2-X2 in FIG. 1(b)and FIG. 5(b) corresponds to the cross-sectional view of the lightemitting device, taken along arrow line X3-X3 in FIG. 1(b).

FIGS. 6(a) and 6(b) are cross sectional views illustrating manufacturingsteps of a light emitting device according to the first embodiment ofthe present invention. FIG. 6(a) corresponds to the cross-sectional viewof the light emitting device, taken along arrow line X1-X1 in FIG. 1(b)and FIG. 6(b) corresponds to the cross-sectional view of the lightemitting device, taken along arrow line X2-X2 in FIG. 1(b).

FIG. 7(a) is a perspective, part transmissive view of an example of alight emitting device according to a second embodiment of the presentinvention, and FIG. 7(b) is a plan, part transmissive view, viewed fromthe light emitting surface side of the light emitting device shown inFIG. 7(a).

FIG. 8(a) is a cross-sectional view of the light emitting device, takenalong arrow line Y-Y in FIG. 7(b), and FIG. 8(b) is a schematic diagramof a light emitting element of the light emitting device shown in FIG.7.

FIGS. 9(a) and 9(b) are cross sectional views illustrating manufacturingsteps of a light emitting device according to the second embodiment ofthe present invention, and FIGS. 9(a) and 9(b) each corresponds to thecross-sectional view of the light emitting device, taken along arrowline Y-Y in FIG. 7(b).

FIGS. 10(a) and 10(b) are cross sectional views illustratingmanufacturing steps of a light emitting device according to the secondembodiment of the present invention, and FIGS. 10(a) and 10(b) eachcorresponds to the cross-sectional view of the light emitting device,taken along arrow line Y-Y in FIG. 7(b).

FIGS. 11(a) and 11(b) are cross sectional views illustratingmanufacturing steps of a light emitting device according to the secondembodiment of the present invention, and FIGS. 11(a) and 11(b) eachcorresponds to the cross-sectional view of the light emitting device,taken along arrow line Y-Y in FIG. 7(b).

FIG. 12 is a cross sectional view illustrating a manufacturing step of alight emitting device according to the second embodiment of the presentinvention, and corresponds to the cross-sectional view of the lightemitting device, taken along arrow line Y-Y in FIG. 7(b).

FIG. 13 is a schematic perspective view of a light source deviceaccording to a second embodiment of the present invention.

FIG. 14(a) is a perspective, part transmissive view of an example of alight emitting device according to a third embodiment of the presentinvention, and FIG. 14(b) is a plan, part transmissive view, viewed fromthe light emitting surface side of the light emitting device shown inFIG. 14(a).

FIG. 15(a) is a cross-sectional view of the light emitting device, takenalong arrow line X2-X2 in FIG. 14(b), and FIG. 15(b) is a schematicdiagram of a light emitting element of the light emitting device, takenalong arrow line X1-X1 in FIG. 14(b).

FIG. 16 is a schematic perspective view of another example of a lightemitting device according to the third embodiment of the presentinvention.

FIGS. 17(a) and 17(b) are cross-sectional views of yet another exampleof a light emitting device according to a fourth embodiment of thepresent invention.

FIG. 18(a) is a perspective, part transmissive view of an example of alight emitting device according to a fourth embodiment of the presentinvention, and FIG. 18(b) is a plan, part transmissive view, viewed fromthe light emitting surface side of the light emitting device shown inFIG. 18(a).

FIG. 19 is a cross-sectional view of the light emitting device, takenalong arrow line Y-Y in FIG. 18(b).

FIG. 20 is a schematic cross-sectional view showing a semiconductordevice according to a fifth embodiment of the present invention.

FIG. 21 is a diagram illustrating a manufacturing step of a lightemitting device according to the fifth embodiment of the presentinvention.

FIGS. 22(a) and 22(b) are diagrams illustrating a manufacturing step ofa light emitting device according to the fifth embodiment of the presentinvention.

FIGS. 23(a) and 23(b) are diagrams illustrating a manufacturing step ofa light emitting device according to the fifth embodiment of the presentinvention.

FIGS. 24(a) and 24(b) are diagrams illustrating a manufacturing step ofa light emitting device according to the fifth embodiment of the presentinvention.

FIGS. 25(a) and 25(b) are schematic cross-sectional views showing asemiconductor device according to a sixth embodiment of the presentinvention.

FIG. 26 is a schematic cross-sectional view showing a variant example ofthe semiconductor device according to fifth and sixth embodiments of thepresent invention.

FIGS. 27(a) and 27(b) are schematic cross-sectional views each showinganother variant example of the semiconductor device according to thepresent invention.

FIGS. 28(a) and 28(b) are schematic cross-sectional views each showinganother variant example of the semiconductor device according to thepresent invention.

FIGS. 29(a) and 29(b) are SEM (Scanning Electron Microscope) images eachshowing an example of deposition of the filler, cross-section partiallyenlarged image near the bottom surface of the recess of the lightemitting device.

FIG. 30 is a SEM image according to a third embodiment.

FIGS. 31(a) and 31(b) are each partially enlarged image near a sidesurface of the light emitting device shown in FIG. 30.

FIGS. 32(a) and 32(b) are SEM images according to other variantexamples.

DETAILED DESCRIPTION OF EMBODIMENTS

Preferred embodiments of the supporting member and the light emittingdevice according to the present invention will be described below withreference to the drawings. The sizes and the arrangement relationshipsof the members in each of drawings are occasionally shown exaggeratedfor ease of explanation. In the description below, the same designationsor the same reference numerals denote the same or like members andduplicative descriptions will be appropriately omitted. In the fifth andsixth embodiments and the variant examples thereof, different referencenumerals may be used for the sake of expedience.

First, arrangements which include a base member will be described in thefirst to fourth embodiments. In the first to fourth embodiments, a lightemitting device having a FD element is indicated by reference numeral100 (first and third embodiments) and a light emitting device having aFU element is indicated by reference numeral 200 (the second and fourthembodiments).

First Embodiment

In a first embodiment, a light emitting device which uses a FD elementwill be described. First, a general construction of a light emittingdevice will be described with description of each component, then, thematerial or the like of each member will be described.

<General Construction>

As shown in FIG. 1 and FIG. 2, the light emitting device 100 includes alight emitting element 104 having a semiconductor layer 11 and atransparent substrate (hereinafter may be referred to as a substrate)10, a reflective member 114 applied so that at least a portion of a sidesurface and the upper surface of the transparent substrate 10 areexposed and a side surface of the semiconductor layer 11 is coveredtherewith, and the light transmissive member 108 which covers theportions exposed from the reflective member 114.

In the present embodiment, as shown in FIG. 1 and FIG. 2, the lightemitting device 100 is a light emitting device 100 having at least onelight emitting element 104 (two are shown in the figures) mountedthereon, and primarily has a base member 101, electrically conductivemembers 102 a, 102 b disposed on the base member 101, a light emittingelement 104 mounted on the electrically conductive members 102 a, 102 b,a reflective member (in the embodiment, an insulating filler 114 isused) which covers at least a portion of the surfaces of theelectrically conductive members 102 a, 102 b which do not have the lightemitting element mounted thereon, and a light transmissive member 108which covers the light emitting element 104. Further in the embodiment,a metal member 103 which is disposed on the electrically conductivemembers 102 a and 102 b on the base member 101, a protective member 105,and wires 106 are disposed.

(Base Member)

The base member 101 is to house and protect the electric components suchas the light emitting element 104 and the protective element 105.

As shown in FIG. 2(a), the base member 101 has a recess 109 which opensupward, and with the recess 209 a, the bottom surface 220 a and the sidesurface 230 a are formed. The electrically conductive members 102 a, 102b are disposed on the bottom surface 120 of the recess 109.

For the material of the base member 101, an insulating member ispreferable and a member which allows little light emitted from the lightemitting element 104 and outside light to pass through is preferable.Also, a material which has a certain degree of mechanical strength ispreferable. Specific examples thereof include ceramics (Al₂O₃, AlNetc.,) and a resin such as a phenol resin, an epoxy resin, a polyimideresin, a BT resin (bismaleimide triazine resin), and a polyphthalamide(PPA). In the case where a resin is used for the material of the basemember 101, inorganic filler such as glass fiber, SiO₂, TiO₂, Al₂O₃ maybe mixed into the resin to improve mechanical strength, decrease thecoefficient of thermal expansion, and improve the optical reflectance.

(Electrically Conductive Member)

The electrically conductive members 102 a, 102 b are to electricallyconnect outside and the electronic components such as the light emittingelement 104 and the protective element 105, and to supply current(power) from an outside supply to those electronic components, and alsothe surfaces thereof are to be covered with the insulating filler. Thatis, the electrically conductive members serve as the electrodes or aportion thereof to supply electricity from outside.

As shown in FIG. 2(a), the electrically conductive members 102 a, 102 bare disposed also on the back surface 140 of the base member 101 so asto be respectively electrically connected to the electrically conductivemembers 102 a, 102 b (respectively to be an electrically single member)in the base member 101. With such a structure as described above, theelectrically conductive members 102 a, 102 b are used as the electrodematerial for supplying electricity and also are to serve as heatdissipation members. The electrically electrically conductive members102 a, 102 b may also be respectively disposed extended to a sidesurface (side wall) 130 in the recess 109 of the base member 101.

Further, in the present embodiment, the electrically conductive members102 a, 102 b have a positive electrode or a negative electroderespectively, which are disposed on the base member 101 spaced apartfrom each other, and at least a portion between the electrodes iscovered with the filler 114. That is, the electrically conductivemembers 102 a, 102 b are separately disposed on the base member 101 in ahorizontal manner (laterally) with respect to the base member 101, sothat the electrically conductive member 102 a serves as a positiveelectrode (anode) and the electrically conductive member 102 b serves asa negative electrode (cathode). With the arrangement as described above,a slit (groove) G is formed between the electrodes (between theelectrically conductive members 102 a and 102 b). Then, the lightemitting element 104 is disposed to straddle the electrically conductivemembers 102 a and 102 b.

At least a portion between the electrodes (electrically conductivemembers 102 a, 102 b), i.e., the silt (groove) G in the conductiveportion is preferably covered with the filler 114 as to be describedlater (see FIG. 5(b)). With this arrangement, light can be preventedfrom leaking through the groove G. In the case where the groove G iscompletely covered with the filler 114, downward leakage of lightthrough the groove G can be more effectively prevented. It is furtherpreferable that the groove G is completely covered with the filler and80% or greater portion of the area in the light emitting deviceirradiated with the light which is other than the light emitting element104 is covered with the filler. The width of the groove G is preferably200 μm or less. The width of the groove G of 200 μm or less facilitatescovering of the groove portion with the filler 114. It is morepreferable that the width of the groove G of 100 μm or less morefacilitates covering of the groove portion with the filler. It isfurther preferable that the groove G is completely covered with thefiller.

The lower limit is not limited but in terms of preventing contactbetween the electrodes, 30 μm or greater is preferable. The filler 114may extend and cover the groove G located under (below) the lightemitting element 104. The groove G located under (beneath) the lightemitting element 104 and the area between the bonding member 111 arecovered with a light transmissive member 108 in addition to by thefiller 114. The groove G may not be covered with the filler 114 and notbe filled with the light transmissive member 108. Moreover, in the casewhere the groove G is not covered with the filler 114, the groove G maybe covered by applying a coating of a light blocking resin.

The materials of the electrically conductive members 102 a, 102 b can beappropriately selected based on the material used for the base member101 and on the method of manufacturing the light emitting device 100.For example, in the case where ceramics is used for the material of thebase member 101, the materials of the electrically conductive members102 a, 102 b preferably have a high melting point so as to be able toendure the firing temperature of the ceramics sheet, and for example, ametal having a high melting point such as tungsten and molybdenum ispreferably used.

In the case where a glass epoxy resin or the like is used for thematerial of the base member 101, it is preferable that the electricallyconductive members 102 a, 102 b are respectively made of a material thatis easy to process. In the case where an injection-molded epoxy resin isused for the material of the base member 101, the electricallyconductive members 102 a, 102 b are respectively made of a material thatis easy to process byway of punching, etching, bending, or the like, andalso that has relatively high mechanical strength. Examples thereofinclude a metal such as copper, aluminum, gold, silver, tungsten, iron,and nickel or an iron-nickel alloy, a phosphor bronze, an ironcontaining copper and molybdenum.

(Metal Member)

A metal member may be disposed to cover the surface of the electricallyconductive member. In the present specification, the term “filler thatcovers the surface of the electrically conductive members” includes thestate in which the electrically conductive members are covered with afiller material which is disposed on a metal member disposed on therespective electrically conductive members. The metal member can beomitted.

The metal member 103 is used to cover the surfaces of the electricallyconductive members 102 a, 102 b to improve the efficiency of lightreflection at the electrically conductive members 102 a, 102 b. Themetal member 103 can be omitted. The metal member 103 is not necessarilymade of a material which has high reflectance and may be disposedintegrally to the respective electrically conductive members 102 a, 102b.

As shown in FIG. 2(a), above the base member 101, that is, the metalmember 103 is disposed on the respective electrically conductive members102 a, 102 b at the bottom surface 120 of the recess 109. Also, as shownin FIG. 2(a), the surfaces of the electrically conductive members 102 a,102 b exposed at the back surface 140 of the base member 101 may berespectively covered with the metal member 103. The metal member 103 isnot necessarily disosed on the electrically conductive members 102 a,102 b which are embedded in the base member 101.

The material of the metal member 103 is not specifically limited as longas the material can be plated, and for example, singly silver, or analloy of silver and a metal having high reflectance such as copper,gold, aluminum, or rhodium, or a multilayer film made with silver andthe above-described alloys can be used. It is preferable to singly usegold which has excellent thermal conductivity. The metal member 103 ispreferably a thin metal foil with a thickness of about 0.05 ⋅m to 50 ⋅m,and in the case where the metal member 103 is formed with a multilayer,the total thickness is preferably in this range. For the method offorming the metal member 103, a sputtering method, a vapor-depositionmethod or the like can be employed, as well as a plating method. Evenwithout a use of silver which has excellent reflectance for the metalmember 103, the insulating filler 114 with light reflectivity is usedfor the covering, so that deterioration in the light extractionefficiency can be prevented.

(Light Emitting Element)

The light emitting element 104 is a FD element which has patternedelectrodes on one principal surface, and is bonded by the bonding member111, mounted (in a flip-chip mounting manner) on the bottom surface 120of the recess 109, and connected to the electrically conductive members102 a, 102 b through the bonding member 111 and the metal member 103.

The light emitting element 104 has, as shown in FIG. 2(b), a base member10 and a semiconductor layer 11 stacked on the base member 10. Thesemiconductor layer 11 includes an n-type semiconductor layer, an activelayer, and a p-type semiconductor layer stacked in this order. An n-typeelectrode 16 is formed on the n-type semiconductor layer and a p-typeelectrode 14 is formed on the p-type semiconductor layer. In the case ofa FD element which is mounted in a face-down mounting manner, theelectrodes formed on the semiconductor layer 11 are fixed on theelectrically conductive members 102 a, 102 b. For the method of mountingthe light emitting element 104, mounting with a use of a solder paste asthe bonding member 111 as shown in FIG. 4(a) or with a use of a bumpmade of a solder or the like is employed. The semiconductor layer 11 ofthe light emitting element 104 is, as shown in FIG. 2(b), preferablycovered with an insulating protective film 13. The light emittingelement 104, which is a FD element shown in FIG. 2(b), is furthersimplified in other figures.

For the light emitting element 104, a light emitting diode is preferablyused, and of an appropriate wavelength can be selected. For example, forthe light emitting element 104 of blue color (light of wavelength range430 nm to 490 nm) or green color (light of wavelength range 490 nm to570 nm), ZnSe, a nitride-based semiconductor (In_(X)Al_(Y)Ga_(1-X-Y)N,0.X, 0.Y, X+Y.1), GaP or the like, can be used. For the light emittingelement 104 of red color (light of wavelength range 620 nm to 750 nm),GaAlAs, AlInGaP, or the like, can be used. Further, a semiconductorlight emitting element made of a material other than described above canalso be used.

In the case where the light emitting device 100 employs a fluorescentmaterial, a nitride semiconductor (In_(X)Al_(Y)Ga_(1-X-Y)N, 0.X, 0.Y,X+Y.1) capable of emitting light of a short wavelength that canefficiently excite the fluorescent material is suitably used. Theemission wavelength of the light emitting element can be variouslyselected by adjusting the materials and their mixed crystal of thesemiconductor layer 11. The structure of the light emitting element 104can be selected from a structure in which both the electrodes aredisposed on the semiconductor layer 11 which is disposed on the basemember 10, or a structure in which the electrodes are disposed in a upand down direction, on the upper surface of the semiconductor layer 11and the surface of the base member 10 respectively. A light emittingelement 104 made of a material other than the above may also be used.The composition, emission color, size, number, or the like, of the lightemitting element 104 can be selected appropriately according to thepurpose. Moreover, a light emitting element 104 capable of emittingultraviolet light or infrared light can also be employed as well as alight emitting element 104 capable of emitting visible light.

(Filler (Reflective Member))

The filler 114 is insulating and is used to cover the conductiveportions of the light emitting device 100, and serves to preventdeterioration of the light extraction efficiency.

The reflective member 114 is preferably a white filler, and preferablyprimarily made of an inorganic compound.

As shown in FIG. 2(a), among the surfaces of the metal member 103 on theelectrically conductive members 102 a, 102 b formed on the bottomsurface 120 of the recess 109, the portions which do not have the lightemitting element 104 and the protective member 106 mounted thereon arecovered with the filler 114. The region around the light emittingelement 104, the side surfaces of the bonding member 111, and theexposed portion in the slit in the electrically conductive portion arecovered with the filler 114.

As described above, covering the electrically conductive members withthe filler 114 enables to suppress the absorption of the light. Theregions which is covered with the filler 114 is, at the light extractingsurface side of the light emitting device 100, mainly the regions wherethe electrically conductive portion (electrically conductive body) isexposed. It is preferable to cover at least 50% of the exposed portionof the electrically conductive body. Further, it is preferable thatsubstantially entire area of the exposed surface of the conductive bodyis covered. The portions covered with the insulating member do not allowtreatments such as an electrodeposition coating which to be describedlater, so that the filler 114 is hardly applied thereon.

Moreover, it is preferable that with the filler 114, the protectiveelement 105 and the electrically conductive wires 106 are covered. Theelectrically conductive members 102 a, 102 b which are exposed on theback surface of the base member 101 are not covered with the filler 114.

In the light emitting element 104, the semiconductor layer 11 is coveredwith the protective film (insulating film) 13. In the present invention,at least a portion of the side surfaces and the upper surface of thetransparent substrate 10 are exposed, and the side surfaces of thesemiconductor layer 11 are covered with the filler 114. That is, in thisspecification, all of the side surfaces of the semiconductor layer 11 iscovered with the filler 114 and a portion of the side surfaces of thebase member 10 are covered with the filler 114, and other portion of theside surfaces and the upper surface of the base member 10 are exposedfrom the filler 114.

At least a portion of the side surfaces and the upper surface of thebase member 10 are exposed, so that the absorption of the light by thefiller (reflective member) 114 can be suppressed, and accordingly,deterioration of the light extraction efficiency can be prevented. Thatis, at least a portion of the side surfaces and the upper surface areexposed from the filler 114, so that emission from the light emittingelement 104 is not blocked by the filler 114, and thus deterioration ofoutput power of the light from the light emitting element 104 can beprevented.

Also, if a resin is applied to coat the electrically conductive members102 a, 102 b etc., the resin rises to the side surfaces of the basemember 10 and eventually all of the side surfaces of the base member arecovered with the resin. In the case where the viscosity of the resin isadjusted to prevent the resin from rising up, the contained amount ofthe light-reflective material is increased to increase the viscosity,which makes it difficult to thinly cover the entire surfaces of theelectrically conductive members. In the present invention, such a resinis not employed. Thus, the filler 114 can be applied on the electricallyconductive members 102 a, 102 b, or the like, without covering allportions of the side surfaces of the base member 10. The side surfacesof the semiconductor layer 11 are covered with the filler 114, and thusthe light extraction efficiency can be improved. Moreover, in the casewhere the light transmissive member 108 contains a fluorescent material,the semiconductor layer 11 can be prevented from being embedded in theprecipitated fluorescent material. Therefore, the absorption of thelight by the fluorescent material can be prevented and deterioration ofthe light extraction efficiency can be prevented. Conversion of light bythe fluorescent material can be carried out at the light extracting sideas much as possible, and this can also contribute to suppression ofdeterioration of the light extraction efficiency.

Electrodeposition coating and the like to be described later is notapplicable to an insulating substrate such as a sapphire substrate.Therefore, the base member 10 is not generally covered with the filler114 by way of electrodeposition coating and the like, but according tothe coating amount or the thickness of the filler 114, the surfaces (aportion of the side surfaces of the base member 10 (lower portion of thebase member 10)) may be covered with the filler 114. The semiconductorlayer 11 which has not covered with the protective film 13 is coveredwith the filler 114. As shown in FIG. 8(b), in the case where a FUelement is used for the light emitting element 204 and where a joininglayer 123, which is an electric conductor is disposed at a lower portion(back surface) of the base member 20, a portion of the filler 114 alsoadheres to the joining layer 123 at the back surface of the substrate20.

For the filler 114, a filler of white color further facilitates toreflect light, so that the light extracting efficiency can be improved.Also, for the filler 114, an inorganic compound is preferably used. Theterm “white color”, as used here, refers to that the filler itself has awhite color, or even in the case where the filler is transparent, thefiller appears white when there is a difference in the refractive indexbetween the filler and the materials around the filler.

Here, the reflectance of the filler 114 is preferably 50% or greater,more preferably 70% or greater with respect to the light of emissionwavelength. With the construction as described above, the lightextracting efficiency of the light emitting device 100 can be improved.

Moreover, the surface area of a single light emitting element 104 whichis covered with the filler 114 is preferably less than 50% of the entiresurface area of the single light emitting element 104. With thisarrangement, the ratio of the emission from the light emitting element104 which is blocked by the filler 114 can be low, so that deteriorationof optical output power of the light from the light emitting element 104can be prevented. In the case where a plurality of light emittingelements 104 are mounted, each of all the light emitting elements has asurface area covered with the filler 114 which is less than 50% of theentire surface area of a single light emitting element 104. Also, thefiller 114 preferably covers 50% or greater surface (exposed portion) ofthe protective element 105. With this arrangement, absorption loss oflight by the protective element 105 can be prevented.

Examples of the material contained in the filler 114 made of aninorganic compound includes an oxide such as SiO₂, Al₂O₃, Al(OH)₃,MgCO₃, TiO₂, ZrO₂, ZnO₂, Nb₂O₅, MgO, Mg(OH)₂, SrO, In₂O₃, TaO₂, HfO,SeO, and YnO₃, a nitride such as SiN, AlN, and AlON, and a fluoride suchas MgF₂. Those may be used singly or as a mixture. Those may be used ina stacked configuration.

The particle diameter of the filler 114 is preferably about ø1 nm to 10μm. Adjusting the particle diameter of the filler 114 in this range,which is suitable particle diameter for covering, facilitates applyingof the filler 114. The particle diameter of the filler 114 is preferablyø100 nm to 5 μm, further preferably ø200 nm to 2 μm. The shape of thefiller particles may be spherical shape or a scale shape.

Here, in FIGS. 29(a), (b), as an example of the state where the filleris deposited, a partially enlarged SEM image of a cross section near thebottom surface 120 of the recess 109 of the light emitting device 100 isshown. In FIG. 29(a), one scale is 2 μm, and in FIG. 29(b), one scale is0.2 μm.

In the images, the filler 114 (including a spherical shape and a scaleshape) with a particle diameter of about ø250 nm are deposited on theelectrically conductive member 102 a (here, on the metal member 103,because the metal member 103 is formed) by using electrophoresis, andthe light transmissive member 108 is impregnated in the filler 114. Atthis time, the filler 114 is preferably contained greater than 50 volume%, further preferably greater than 65 volume % with respect to the lighttransmissive member 108 which is impregnated in the filler 114. Fromanother viewpoint, when observing the cross section at a portion wherethe filler 114 having the light transmissive member 108 impregnatedtherein, the filler 114 is preferably exposed at 50% or greater, morepreferably 65% or greater, at the cross sectional area.

Here, in the case where the filler 114 is contained in a resin materialand is applied for coating, if greater than 65 volume % of the filler114 with respect to the resin material is contained, moldabilitydecreases. Even in the case of 65 volume % or less, the resin amount isdifficult to control, and further, appropriately disposing apredetermined amount of resin to a predetermined position is alsodifficult. However, according to the method of manufacturing accordingto the present embodiment which to be described later, the filler 114can be applied with high density while reducing the thickness.

(Light Transmissive Member)

The light transmissive member 108 is for protecting the light emittingelement 104, the protective element 105, the wire 106, the filler 114,and the like, from dust, moisture, external force, or the like. As shownin FIG. 2(a), the inner portion of the recess 109 of the base member 101is covered (enclosed) with the light transmissive member 108. Also, inorder to improve the adhesion between the filler 114 and the lighttransmissive member 108, the light transmissive member 108 is preferablyimpregnated between the filler particle 114 and the filler particle 114,that is, the gaps among the filler 114. In the case where the lightemitting element 104 is a FD element, and the periphery of the lightemitting element 104 is covered with a light blocking member, the lighttransmissive member 108 can be omitted.

The material of the light transmissive member 108 preferably hastransparent property capable of allowing light from the light emittingelement 104 to pass through it. Examples of such material include asilicone resin, an epoxy resin, and a urea resin. In addition to thesematerials, a coloring agent, a light diffusing agent, a filler, afluorescent material or the like may also be contained as needed. Thelight transmissive member 108 can be made of a single member, or madewith two or more of plurality of layers. The filling amount of the lighttransmissive member 108 is sufficient to cover the light emittingelement 104 mounted on the recess of the base member 101, the protectiveelement 105, the wires 106, or the like. In the case where the lighttransmissive member 108 functions as a lens, the surface of the lighttransmissive member 108 may be formed with a protrusion to form a shellshape, a convex lens shape, or the like.

(Wire)

The wires 106, 206 (see FIG. 8) are used to electrically connect theelectrode terminals of the FU elements or the protective element 105 tothe respective portions which serves as the electrodes of theelectrically conductive members 102 a, 102 b disposed in the recess 109of the base member 101. Examples of the material of the wires 106, 206include a metal such as gold, copper, platinum, and aluminum, and analloy of those, but particularly, gold which has excellent thermalconductivity is preferably used.

(Protective Element)

The protective element 105 serves as, for example, a Zener diode, and isdisposed when needed. As shown in FIG. 4(b), the protective element 105is mounted at the bottom surface 120 of the recess 109 through a bondingmember 110, for example an Ag paste, and connected to the electricallyconductive member 102 a through the metal layer (not shown) and themetal member 103 which are disposed at the bottom surface of theprotective element 105. In addition, a wire 106 is connected to theupper surface of the protective element 105. The wire 106 is connectedto the electrically conductive member 102 b through the metal member103, and thus, the protective element 105 and the electricallyconductive member 102 b are electrically connected.

(Bonding Member)

The bonding member (die-bonding member) 111 is for electricallyconnecting the electrodes of the light emitting element 104 and theelectrically conductive members 102 a, 102 b respectively, and also forbonding the light emitting element 104 to the base member 101. For thebonding member 111, an electrically conductive member is used. Examplesof the material include an alloy containing Au, an alloy containing Ag,an alloy containing Pd, an alloy containing In, a alloy containingPb—Pb, an alloy containing Au—Ga, an alloy containing Au—Sn, an alloycontaining Sn, an alloy containing Au—Ge, an alloy containing Au—Sr, analloy containing Al, an alloy containing Cu—In, and a mixture of a metaland a flux.

In the case where the light emitting device is mounted in a face-upmounting manner, an electrically conductive member is not necessarilyused for the bonding member 111, and an insulating resin (a resincomposition such as an epoxy resin, a silicone resin, or the like, canbe used.

Also, the bonding member 111 in a form of liquid, paste or solid (in asheet shape, a brick shape, or a powder form) can be used, which can beappropriately selected according to the composition, the shape of thebase member 101, or the like. The bonding member 111 described above maybe made of a single member or a combination of several kinds of members.Further, in the case where a light transmissive bonding member, inparticular, is used, a fluorescent member capable of absorbing the lightfrom the semiconductor light emitting element and emitting light ofdifferent wavelength can be contained in the bonding member.

(Wavelength Converting Member)

The light transmissive member 108 and/or a light blocking member 207(see FIG. 8(a)) may include a fluorescent member as the wavelengthconverting member that absorbs at least a part of the light emitted fromthe light emitting element 104 and emits light of different wavelength.

A fluorescent member capable of converting light from a light emittingelement 104 into light of a longer wavelength has a higher efficiency.The fluorescent member may be formed of a single layer of one kind offluorescent material etc., or a single layer of a mixture of two or morekinds of fluorescent materials etc. Or, a stacked layer of two or moresingle layers containing one kind of fluorescent material, or a stackedlayer of two or more single layers each containing a mixture of two ormore kinds of fluorescent materials etc., can be employed.

It is sufficient that the fluorescent member is capable of absorbing thelight from the semiconductor light emitting element which has anitride-based semiconductor as its semiconductor layer and emittinglight of different wavelength. For example, a nitride-based fluorescentmaterial or oxynitride-based fluorescent material, activated mainly witha lanthanoid element such as Eu, Ce can be used. More specifically, thefluorescent member is preferably at least one selected from the broadlygrouped into (1) to (3) described below.

(1) Fluorescent materials such as an alkaline-earth halogen apatitefluorescent material, an alkaline-earth metal borate halogen fluorescentmaterial, an alkaline-earth metal aluminate fluorescent material, analkaline-earth sulfide fluorescent material, an alkaline-earththiogallate fluorescent material, an alkaline-earth silicon nitridefluorescent material, and a germinate each activated mainly with alanthanoid element such as Eu and/or a transition-metal element such asMn; (2) Fluorescent materials such as a rare-earth aluminate, arare-earth silicate, an alkaline-earth metal rare-earth silicate, eachactivated mainly with a lanthanoid element such as Ce; and (3)Fluorescent materials such as an organic compound or an organic complexeach activated mainly with a lanthanoid element such as Eu.

Among those, as in (2), a YAG (Yttrium Aluminum Garnet)-basedfluorescent material which is a rare-earth aluminate fluorescentmaterial activated with a lanthanoid element such as Ce is preferable.YAG-based fluorescent materials are represented by the compositionformulas such as in (21) to (24) shown below.

Y₃Al₅O₁₂:Ce  (21)

(Y_(0.8)Gd_(0.2))₃Al₅O₁₂:Ce  (22)

Y₃(Al_(0.8)Ga_(0.2))₅Al₅O₁₂:Ce  (23)

(Y,Gd)₃(Al,Ga)₅O₁₂:Ce  (24)

Moreover, for example, a part or all of Y may be substituted with Tb,Lu, or the like. Specifically, Tb₃Al₅O₁₂:Ce, Lu₃Al₅O₁₂:Ce, or the like,may be used. Further, a fluorescent material other than those describedabove, which has similar properties, performance, and effects can alsobe used.

«Method of Manufacturing Light Emitting Device»

A method of manufacturing the light emitting device according to thefirst embodiment of the present invention will be described below. Inthe present embodiment, a single light emitting device is illustrated,but the base member is processed as an aggregate until divided intoindividual units in the final step, and thus the external side surfacesof the base member are created by the dividing.

FIG. 3 through FIG. 6 are cross sectional views illustratingmanufacturing steps of a light emitting device according to the firstembodiment of the present invention, and FIGS. 3(a) and 3(b) eachcorresponds to the cross-sectional view of the light emitting device,taken along arrow line X2-X2 in FIG. 1(b). FIG. 4(a) corresponds to thecross-sectional view of the light emitting device, taken along arrowline X2-X2 in FIG. 1(b) and FIG. 4(b) corresponds to the cross-sectionalview of the light emitting device, taken along arrow line X1-X1 in FIG.1(b). FIG. 5(a) corresponds to the cross-sectional view of the lightemitting device, taken along arrow line X2-X2 in FIG. 1(b) and FIG. 5(b)corresponds to the cross-sectional view of the light emitting device,taken along arrow line X3-X3 in FIG. 1(b). FIG. 6(a) corresponds to thecross-sectional view of the light emitting device, taken along arrowline X1-X1 in FIG. 1(b). FIG. 6(b) corresponds to the cross-sectionalview of the light emitting device, taken along arrow line X2-X2 in FIG.1(b). FIG. 3 to FIG. 6 show a sequence of steps of manufacturing a lightemitting device 100, which are basically carried out from FIG. 3(a) toFIG. 6(b). Here, FIGS. 5(a), (b), and FIG. 6(a) illustrate a step ofapplying a filler and are carried out at approximately the same time.

One method of manufacturing a light emitting device 100 according to thepresent invention includes a step of forming electrically conductivemembers, a step of die-bonding, a step of applying a filler, and a stepof forming a light transmissive member. In the first embodiment, a metalmember 103 and a protective element 105 are disposed, so that a step offorming a metal member, a step of bonding a protective element, and astep of wire-bonding are included. Hereinafter, each step will bedescribed below.

<Electrically Conductive Member Forming Step>

As shown in FIG. 3(a), the electrically conductive member forming stepis a step of forming electrically conductive members 102 a, 102 b on abase member 101. In the case where the electrically conductive members102 a, 102 b are to be formed on the back surface 140 of the base member101, they are formed in this step. That is, this step is a step todispose the electrically conductive members 102 a, 102 b on the basemember 101.

The electrically conductive members 102 a, 102 b can be obtained by, forexample, in the case where a base member 101 made of ceramic, aconductive paste which contains fine particles of high-melt point metalsuch as tungsten or molybdenum is applied in a predetermined pattern inthe stage of ceramics green sheet before firing, then fired.Alternatively, the electrically conductive members 102 a, 102 b can beformed on a ceramics plate which is already fired, by using a techniqueof, for example such as vacuum vapor deposition, sputtering, or plating.

The recess 109 of the base member can be formed by, for example, forminga through hole of various size in each corresponding ceramics greensheet and stack them. In the case of the side surfaces 130 of therecess, the electrically conductive members 102 a, 102 b can be formedon the side surfaces 130 in the same manner as on the bottom surface120.

In the case where a base member 101 made of a glass epoxy resin is used,the electrically conductive members 102 a, 102 b may be formed byattaching a copper plate to a prepreg which is obtained bysemi-hardening a glass cloth containing an epoxy resin or an epoxyresin, then, patterning the metal member such as copper into apredetermined shape using a photolithographic technique.

<Metal Member Forming Step>

As shown in FIG. 3(a), the metal member forming step is a step offorming a metal member 103, which allows bonding, on the electricallyconductive members 102 a, 102 b formed on the base member 101. In thecase where the metal member 103 is also formed on the electricallyconductive members 102 a, 102 b which are on the back surface 140 of thebase member 101, they are formed in this step. That is, in this step,the metal member 103 is disposed on the electrically conductive members102 a, 102 b.

For disposing the metal member 103, a technique such as a platingtechnique, a sputtering technique, a vapor deposition technique, or atechnique of bonding a thin film, can be used. When a plating techniqueis employed, a technique such as electrolytic plating or nonelectrolytic plating can be used. For example, the most simplifiedtechnique is that after electrically connecting the correspondingportions which are on the electrically conductive members 102 a, 102 b,carrying out an electrolytic plating. In the case where a nonelectrolytic plating technique, a sputtering technique, or a vapordeposition technique is employed, deposition of only on the electricallyconductive members 102 a, 102 b can be obtained by using aphotolithographic technique. Also, after disposing the metal member 103on the electrically conductive members 102 a, 102 b which are not formedin a pattern, patterning can be carried out on the electricallyconductive members 102 a, 102 b and the metal member 103 to obtain apredetermined shape. In the case where wire-bonding is carried out onthe metal member 103 or where the electrodes of the light emittingelement 104 are directly connected, the metal material is needed to besuch that wire-bonding or flip-chip mounting can be applied thereon. Butif those are not performed on the electrically conductive members 102 a,102 b, the kinds of the metal is not needed to be specifically limited.

<Die-Bonding Step>

As shown in FIG. 4(a), the die-bonding step is a step in which a lightemitting element 104 is mounted and bonded on the base member 101 (onthe electrically conductive members 102 a, 102 b in the case where themetal member 103 is not formed) after forming the metal member 103.

The die-bonding step includes light emitting element mounting step inwhich a light emitting element 104 is mounted on the base member 101 andheating step in which after the light emitting element 104 is mounted,the light emitting element 104 is bonded by heating.

(Light Emitting Element Mounting Step)

The light emitting element mounting step is a step in which on the basemember 101, through a bonding member 111, a light emitting element 104is mounted. The bonding member 111 contains, for example, rosin (pineresin) or a thermosetting resin, and further, when needed, a solvent forviscosity control, various additives, an activator such as an organicacid may be contained. Moreover, a metal (for example in a powder form)may be contained.

The light emitting element 104 is bonded with the electricallyconductive members 102 a, 102 b (metal member 103) on the base member101 through the bonding member 111. A flux may be applied beforehand onthe back surface of the light emitting element 104.

Here, it is sufficient that the bonding member 111 is disposed betweenthe electrically conductive members 102 a, 102 b and the light emittingelement 104 through the metal member 103. Therefore, of the portions onthe electrically conductive members 102 a, 102 b, the bonding member 111may be disposed in a region where the light emitting element 104 to bemounted, or the bonding member 111 may be disposed at the light emittingelement 104 side. Or the bonding member 111 may be disposed on the bothof them. Now, bonding method of the light emitting element 104 will bedescribed below.

FIG. 4(a) illustrates a state in which a resin composition (bondingmember) 111 in liquid or paste form is disposed on the electricallyconductive members 102 a, 102 b. In the case where a bonding member 111in liquid or paste form is disposed on the electrically conductivemembers 102 a, 102 b, technique can be appropriately selected from apotting technique, a printing technique, a transferring technique, orthe like, according to the viscosity. Then, to the portion where thebonding member 111 is disposed, the light emitting element 104 ismounted. The electrodes are formed on the joining surface of the lightemitting element 104, and the electrodes and the electrically conductivemembers 102 a, 102 b are respectively electrically connected. In thecase where a bonding member in solid form is used, after disposing thebonding member 111 in solid form, the light emitting element 104 can bemounted on the electrically conductive members 102 a, 102 b in the samemanner as in the case where the bonding member 111 in liquid or pasteform is used. It may be such that the bonding member 111 in solid orpaste form is temporarily melted by heating etc. so that the lightemitting element 104 is fixed to a desired position on the electricallyconductive members 102 a, 102 b.

The amount of the resin composition is preferably adjusted so that afterthe light emitting element 104 is bonded, the bonding area of the resincomposition is approximately the same as or greater than the bondingarea of the light emitting element 104. In the case where a plurality ofthe light emitting elements are mounted by using a resin composition inliquid or paste form, in order to prevent the light emitting elementsfrom moving from the positions due to the surface tension, each of thelight emitting elements 104 is preferably bonded through individuallyprovided bonding member 111. The thickness of the bonding member isadjusted because the suitable thickness of the bonding member differsdepending on the kinds of the bonding members, or in view of the casewhere the bonding member expands in lateral direction by pressed at thetime of mounting the light emitting element, or the case where thebonding member follows uneven contour of the base member.

(Heating Step)

The heating step is a step in which after the light emitting element 104is positioned, the bonding member 111 is heated and the light emittingelement 104 is bonded on the base member 101.

As shown in FIG. 10(a), in the case where a FU element is used for thelight emitting element, the bonding member 111 may be an insulatingmember, and heating in the heating step is carried out at a temperaturehigher than the temperature at which at least a part of the bondingmember 111 is volatilized. In the case where the bonding member 111contains a thermosetting resin, heating to a temperature higher than thecuring temperature is preferable. With this, the light emitting element104 can be bonded and fixed by the thermosetting resin.

Also, for example, in the case where a resin composition containingrosin and a low-melting-point metal are used as the bonding member 111,and where the low-melting-point metal is positioned on the electricallyconductive members 102 a, 102 b (on the metal member 103), heating to atemperature higher than the melting of the low-melting-point metal ispreferable.

Here, particularly in the case where the bonding member 111 containsrosin and the metal is disposed at the light emitting element side, forexample, in the case where a metal film is formed on the sapphire planeof a gallium nitride-based semiconductor element which uses a sapphiresubstrate, or in the case where a metal film is formed on the siliconeplane of a gallium nitride-based semiconductor element which uses asilicone substrate, due to the action of the rosin composition in thebonding member by heat and the phenomenon of interdiffusion in themetal, metallic binding between the electrically conductive members andthe metal film can be formed while removing the insulating member. Withthis, the light emitting element can be fixed more firmly and alsoelectric continuity can be obtained.

In the heating step, following the heating, a washing step can befurther carried out. For example, in the case where a resin compositionis used for the bonding member 111, after eliminating a part of theresin composition by volatilization during the heating, residual resincomposition may be removed by further carrying washing or the like(residual bonding member washing step). Specifically, in the case wherethe resin composition contains rosin, washing is preferably carried outafter heating. For the washing solution, a glycol ether system organicsolvent or the like is preferably used.

<Protective Element Bonding Step>

As shown in FIG. 4(a), in the protective element joining step, afterforming the metal member 103 (after forming the electrically conductivemembers 102 a, 102 b, in the case where the metal member 103 is notformed) on the base member 101, a protective element 105 is positionedand bonded on the base member 101. That is, in the protective elementbonding step, the protective element 105 is disposed on the electricallyconductive member 102 a through the metal member 103 and bonded.

<Wire-Bonding Step>

As shown in FIG. 4(b), in the wire-bonding step, an electrode terminalat the upper portion of the protective element 105 and a portion of theelectrically conductive member 102 b which serves as an electrode areconnected with a wire 106. The technique for connecting the wires 106 isnot specifically limited and any techniques common in the art can beused.

<Filler-Applying Step>

As shown in FIG. 5(a), in the filler-applying step, among the surfacesof the metal member 103 on the electrically conductive members 102 a,102 b, the portions where the light emitting element 104 is not disposedare covered with the filler 114 by using an electrolytic platingtechnique, an electrodeposition coating technique, or an electrostaticcoating technique. With this step, after mounting the light emittingelement 104 using the bonding member 111, the exposed surfaces of themetal member 103 on the base member 101 (on the electrically conductivemembers 102 a, 102 b, in the case where the metal member 103 is notformed) are covered with the filler 114. At this time, at least aportion of the side surfaces and the upper surface of the transparentsubstrate 10 are exposed, and the side surfaces of the semiconductorlayer 11 are covered with the filler 114.

Also, as shown in FIG. 5(b), in the filler-applying step, it ispreferable to also cover the groove G between the electrodes (betweenthe electrically conductive members 102 a, 102 b), and further, as shownin FIG. 6(a), it is preferable to also cover the protective element 105and the wires 106. For applying the filler 114, a deposition techniquesuch as an electrolytic plating technique, an electrostatic coatingtechnique, or an electrodeposition coating technique can be used.

The filler-applying step includes, for example, a step of positioning alight emitting device 100 in a solution which contains filler and a stepof depositing the filler on the light emitting device 100 by usingelectrophoresis in the solution. In such a technique of depositingfiller, in a solution, an electrode which to be arranged opposite to thelight emitting device 100 is placed, and a voltage is applied to theelectrode. Thus, using electrophoresis to drive electrically chargedfiller particles in the solution to deposit the filler 114 on theportions where the metal member 103 is exposed at the electricallyconductive members 102 a, 102 b. The thickness of the deposited filler114 can be appropriately adjusted by conditions and time of deposition,and is preferably at least 5 ⋅m. Further preferably the thickness is 10⋅m or more. By using a material having a high reflectance, alight-reflective layer is formed by the deposited filler 114. After astep of forming the filler 114 by using electrodeposition as describedabove, a member other than the filler 114 may be formed by usingelectrodeposition.

For the electrolytic solution for electrodeposition, a mixed liquid inwhich the filler is dispersed is used. The material of the electrolyticsolution is not specifically limited as long as it allows theelectrically charged filler moves in the solution by electrostaticforce. For example, acid or alkali capable of dissolving the filler, forexample, nitric acid containing alkaline-earth metal ion (such as Mg²)can be contained in the electrolytic solution. In the electrolyticsolution, a metallic alkoxide may be contained. More specifically, anorganic material containing an element selected from Al, Sn, Si, Ti, Y,Pb, or an alkaline-earth metal element, as its constituent element. Forthe material contained in the electrolytic solution, other than asdescribed above, a mixed solution in which filler is dispersed in a solmade with a metal alcholate or a metallic alkoxide and an organicsolution mixed at a predetermined ratio, may be used as the electrolyticsolution. Other than above, the electrolytic solution may be a mixedsolution in which, acetone as an organic solvent, and aluminum sol andfiller as an organic metal material, are contained in a solution whosebase solution is isopropyl alcohol. In the present embodiment, the basemember is in a state of aggregate until divided in the final step, thefiller 114 coating can be applied at once on a plurality of the lightemitting devices and thus leads to excellent mass productivity.

<Light Transmissive Member Disposing Step>

As shown in FIG. 6(b), in the light transmissive member disposing step,a light transmissive member 108 is disposed on the base member 101 tocover the light emitting element 104 with the light transmissive member108. That is, the light transmissive member 108 for covering the lightemitting element 104, the protective element 105, the wires 106, and thelike, is applied in the step such that, a melted resin is injected inthe recess 109 of the base member 101, then, cured by applying heat oroptical irradiation.

An embodiment of the present invention is described above, but thepresent invention is not limited thereto, various changes may be madewithout departing from the scope of the invention. That is, the lightemitting device and the method of manufacturing the light emittingdevice described above are intended as illustrative of a light emittingdevice and a method of manufacturing the light emitting device to give aconcrete form to technical ideas of the present invention, and the scopeof the present invention is not limited to the light emitting device andthe method of manufacturing the light emitting device described above.Furthermore, it should be appreciated that the members shown in claimsattached hereto are not specifically limited to members in theembodiments. Particularly, the sizes, materials, shapes and thearrangement relationships of the members described the preferredembodiments are given as an example and not as a limitation to the scopeof the invention.

For example, in the description above, a light emitting device whichuses a FD element is mainly illustrates, but in the present invention, alight emitting device which uses a FU element may also be made. Thenumber of the light emitting elements mounted on the light emittingdevice is appropriately adjusted and a light emitting device may includea plurality of three or more light emitting elements. Hereinafter, as atypical variant example, a light emitting device which uses a FU elementand a method of manufacturing the light emitting device will bedescribed as a second embodiment.

Second Embodiment

A light emitting device which uses a FU element will be described in asecond embodiment. FIG. 13 shows a perspective view of an example of alight emitting device according to the present embodiment. First, ageneral construction of a light emitting device will be described withdescription of each component, then, the material or the like of eachmember will be described. In what follows, the different points from theabove embodiment of the light emitting device 100 will be mainlydescribed.

(General Construction)

As shown in FIG. 7 and FIG. 8, a light emitting device 200 is a devicein which at least one light emitting element 204 (two in the figures)are mounted, and mainly includes a base member 201, electricallyconductive members 202 a, 202 b, 202 c disposed on the base member 201,light emitting element 204 mounted on the respective portions of theelectrically conductive members 202 a, 202 b, 202 c, a wire 206 whichconnects a portion of the electrically conductive member 202 b, whichserves as an electrode, with an electrode terminal of the light emittingelement 204, an insulating filler 114 which covers a metal member 103,which does not have the light emitting element 204 mounted thereon, anda lower surface of the wire 206, and a light transmissive member 108which covers the light emitting element 204 and the filler 114. Further,in this case, a light blocking member 207 is disposed.

(Base Member)

As shown in FIG. 8(a), the base member 201 has a recess 209 a whichopens upward, and further has recesses 209 b, 209 c in the recess 209 a,and with the recess 209 a, the bottom surface 220 a and the side surface230 a are formed. Further, with the recesses 209 b, 209 c, the bottomsurfaces 220 b, 220 c and the side surfaces 230 b, 230 c are formedrespectively, and between the bottom surfaces 220 b and 220 c, a step isformed. Then, on the bottom surface 220 a of the recess 209 a, theelectrically conductive member 202 a, on the bottom surface 220 b of therecess 209 b, the electrically conductive member 202 b, and on thebottom surface 220 c of the recess 209 c, the electrically conductivemember 202 c, are respectively disposed.

(Electrically Conductive Member)

As shown in FIG. 8(a), the electrically conductive members 202 b, 202 care also disposed on the back surface 240 of the base member 201 so thatin the base member, they are respectively electrically connected to theelectrically conductive members 202 b, 202 c (respectively to be anelectrically single member) of the bottom surfaces 220 b, 220 c of therecesses 209 b, 209 c.

(Metal Member)

As shown in FIG. 8(a), on the base member 201, that is, on theelectrically conductive members 202 a, 202 b, 202 c of the bottomsurfaces 220 a, 220 b, 220 c of the recesses 209 a, 209 b, 209 c, themetal member 103 is disposed respectively. Also, as shown in FIG. 8(a),the surface of the electrically conductive members 202 a, 202 b disposedon the back surface 240 of the base member 201 may also be covered withthe metal member 103. The metal member 103 is not disposed on theelectrically conductive members 202 b, 202 c which are embedded in thebase member 201. The metal member 103 may be disposed integrally to theelectrically conductive members 202 b, 202 c, or the metal member 103may be omitted.

(Light Emitting Element)

The light emitting element 204 is, as shown in FIGS. 8(a), 8(b), a FUelement which has electrodes on its upper surface, and the lower surfaceof the light emitting element 204, a joining layer 123 is formed. Thejoining layer 123 formed on the light emitting layer 204 is connected tothe bonding member 111 which is at a surface of the electricallyconductive member 202 a, the metal member 103, and the bonding member111 disposed in this order on the bottom surface 220 a of the recess 209a. Though, the bonding member 111 is not shown in the figuresillustrating a light emitting device 200 of the second embodiment.

As shown in FIG. 8(b), the light emitting element 204 has, a base member20 and a semiconductor layer 21 stacked on the base member 20. Further,on the back surface of the base member 20, an Ag/Pt/AuSn film (stackedin this order, from the left) with a pattern may be disposed. Also, atone side of the semiconductor layer 21, an n-electrode (n-pad electrode)25 b which is an electrode terminal is disposed, and at the other side,a p-pad electrode 25 a which is an electrode terminal is disposedthrough the electrode 24. The pad electrodes 25 a, 25 b are disposed onthe same side of the semiconductor layer 21, and are electricallyconnected to respective portions of the electrically conductive members202 b, 202 c which serve as electrodes by wires 206 (see FIG. 7(b)).Then, the portions of the semiconductor layer 21 of the light emittingelement 204 are covered with the insulating protective film (insulatingfilm) 23, except for the portions for connecting to each of the padelectrodes 25 a, 25 b with the respective wires 206. The light emittingelement 204, which is a FD element shown in FIG. 8(b), is furthersimplified in other figures.

In the embodiment, the width of the joining layer (the reflective layer22 a, the barrier layer 22 b, and the adhesive layer 22 c) is smallerthan the width of the light emitting element 204, that is, the width ofthe substrate 20. As described above, when the width of the joininglayer is smaller than the width of the substrate 20, the joining layeris not cut in the step of dividing a wafer into individual lightemitting elements, and therefore, occurrence of detachment of thejoining layer in the dividing step can be avoided. The joining layer 123is, in the case where a FU element is used for the light emittingelement, may be formed with a multilayer structure including areflective layer 22 a and a barrier layer 22 b in addition to theadhesive layer 22 c which bonds the light emitting element 204 to thebase member 201.

The reflective layer 22 a is a layer for reflecting light emitted by thelight emitting element 204 into the substrate 20 and the semiconductorlayer 21. With this arrangement, light can be extracted to outside fromend surfaces of the light emitting element 204 other than that has thereflective layer 22 a formed thereon. Specifically, a material such asAg, Al, Rh, Pt, or Pd is preferably used. For example, with a use of Agor an Ag alloy, an element having high reflectance and good lightextraction can be obtained.

The barrier layer 22 b is a layer for preventing diffusion of othermaterials, particularly the material of adhesive layer 22 c.Specifically, a material having a high melt point such as W, Mo, or suchas Pt, Ni, Rh, Au is preferably used.

The adhesive layer 22 c is for adhering the light emitting element 204to the base member 201. Examples of the material thereof include analloy of In, Pb—Pd system, Au—Ga system, alloy system of Au with Ge, Si,In, Zn, or Sn, alloy system of Al with Zn, Ge, Mg, Si, or IN, alloysystem of Cu with Ge or In, Ag—Ge system, and Cu—In system. Preferableexample thereof include a eutectic alloy film such as an alloy whosemain components are Au and Sn, an alloy whose main components are Au andSi, and an alloy whose main components are Au and Ge. Among those, AuSnis specifically preferable.

(Filler)

As shown in FIG. 8(a), of the surfaces of the metal member 103 on theelectrically conductive members 202 a, 202 b, 202 c respectivelydisposed on the respective bottom surfaces 220 a, 220 b, 220 c of therecesses 209 a, 209 b, 209 c, the portions where a light emittingelement 204 is not mounted are covered with the filler 114. Further, thefiller 114 covers the entire surface, such as the areas peripheral tothe light emitting elements and the side surfaces of the joining layer123 under the light emitting elements, as well as the lower surface ofthe wires 206. That is, of the portions of the electrically conductivemembers 202 a, 202 b, 202 c, other than the regions where the lightemitting elements 204 are mounted, are covered with the filler 114.

(Light Transmissive Member)

As shown in FIG. 8(a), the inner portion of the recess 209 a of the basemember 201 is enclosed with the light transmissive member 108. Althoughthe light transmissive member 108 is not disposed on the portions wherethe light blocking member 207 is embedded, in the case where the lightblocking member is not disposed, the light transmissive member 108 isdisposed on those portions (in the recesses 209 b, 209 c). The lighttransmissive member 108 may be disposed as needed.

(Light Blocking Member)

The light blocking member 207 is preferably a member capable ofreflecting light, and embedded in the recesses 209 b, 209 c of the basemember 201 to cover the exposed portions of the base member 201 whichare exposed at the side surfaces 230 a, 230 b, 230 c of the recesses 209b, 209 c. The exposed portions (side surfaces 230 a, 230 b, 230 c) ofthe base member 201 may become a source of optical transmission losswhich causes optical loss while allowing light to pass therethrough.Therefore, disposing the light blocking member 207 having lightreflective function on those portions enables to prevent the loss due totransmission and absorption of light. As described above, the side wallsof the base member 201 and at least a portion of the filler 114 arepreferably covered with the light blocking member 207. With thisarrangement, light from the light emitting elements 204 is reflected bythe light blocking member 207, and thus the light extracting efficiencycan be improved. The light blocking member 207 is not limited to thatdescribed in the present embodiment, and may be used in the lightemitting devices according to the first embodiment.

As shown in FIG. 8(a), in the inner portion of the recesses 209 b and209 c of the base member 201, the light blocking member 207 is embedded.The light blocking member 207 is preferably disposed so that therecesses 209 b, 209 c are entirely embedded, and is further preferablydisposed so that the exposed portions of the side surfaces 230 a areentirely covered.

The light blocking member 207 is a member capable of efficientlyreflecting light emitted from the light emitting element 204 andpreferably made of an insulating material that absorbs little light andhas high resistance against light and heat. Examples of such materialinclude a silicone resin, an epoxy resin, and a urea resin. In additionto these materials, a coloring agent, a light diffusing agent, a lightreflecting material, a filler, a fluorescent material or the like mayalso be contained as needed. The light blocking member 207 can be madeof a single member, or made with two or more of plurality of layers.

With the light emitting device 200 described above, while the lightemitting device 200 is in operation, among light from the light emittingelement 204 propagating in all directions, light propagating upward isextracted to outside above the light emitting device 200. Lightpropagating downwardly or laterally is reflected at the bottom surfaces220 a, 220 b, 220 c or at the side surfaces 230 a, 230 b, 230 c of therecesses 209 a, 209 b, 209 c of the base member 201, or at the lightblocking members 207, and extracted to outside above the light emittingdevice 200. At this time, because the filler 114 is applied on the metalmembers 103 on the electrically conductive members 202 a, 202 b, 202 cand the conductive portion (conductive body) of the wires 206 and thelike, the absorption of the light by those portions can be suppressedand also light can be reflected by the filler 114. Thus, light from thelight emitting element 204 can be extracted efficiently.

«Method of Manufacturing Light Emitting Device»

Next, a method of manufacturing a light emitting device according to thesecond embodiment of the present invention will be described below withreference to the accompanying drawings. In the present embodiment, asingle light emitting device is illustrated, but the base member isprocessed as an aggregate until divided into individual units in thefinal step, and thus the external side surfaces of the base member arecreated by the dividing.

FIGS. 9 to 12 are cross sectional views illustrating steps ofmanufacturing a light emitting device 200, and correspond to thecross-sectional view of the light emitting device, taken along arrowline Y-Y in FIG. 7(b). FIG. 9 to FIG. 12 illustrate a step sequence ofmanufacturing a light emitting device 200, and basically, themanufacturing is carried out in sequence from FIG. 9(a) to FIG. 12.

One method of manufacturing a light emitting device 200 according to thepresent invention includes an electrically conductive member formingstep, a die-bonding step, a filler-applying step, and a lighttransmissive member forming step. In the second embodiment, a FU elementis used, so that a wire-bonding step is included. Also, in the secondembodiment, a light-blocking member 207 is disposed, so that alight-blocking member forming step is included. Hereinafter, each stepwill be described below.

<Electrically Conductive Member Forming Step>

As shown in FIG. 9(a), the electrically conductive member forming stepis a step of forming the electrically conductive members 202 a, 202 b,202 c on the base member 201. In the case where the electricallyconductive members 202 b, 202 c are formed on the back surface 240 ofthe base member 201, they are formed in this step. That is, in thisstep, the electrically conductive members 202 a, 202 b, 202 c aredisposed on the base member 201. Those others than as described aboveare carried out as in the same manner as that in the first embodiment.

<Metal Member Forming Step>

As shown in FIG. 9(a), the metal member forming step is a step offorming the metal member 103, which allows bonding, on the electricallyconductive members 202 a, 202 b, 202 c formed on the base member 201. Inthe case where the electrically conductive members 202 b, 202 c are alsoformed on the back surface 240 of the base member 201, they are formedin this step. That is, in this step, the metal member 103 is disposed onthe surfaces of the electrically conductive members 202 a, 202 b, 202 c.Those others than as described above are carried out as in the samemanner as that in the first embodiment.

<Die-Bonding Step>

As shown in FIG. 10(a), the die-bonding step is a step of mounting alight emitting element 204, in the die-bonding step, a light emittingelement 104 is mounted and bonded on the base member 201 (on theelectrically conductive members 202 a) having the metal member 103formed thereon. That is, in this step, the light emitting element 204 ismounted and bonded through the bonding member 111 on the bottom surface220 a of the recess 209 a of the base member 201. Those others than asdescribed above are carried out as in the same manner as that in thefirst embodiment.

<Wire-Bonding Step>

As shown in FIG. 10(b), the wire-bonding step includes, using a wire206, electrically connecting a portion on the electrically conductivemember 202 b which serves as an electrode and an electrode terminal (padelectrode) at an upper portion of the light emitting element 204. In thesame manner, the step includes, using a wire 206, electricallyconnecting an electrode terminal (pad electrode) at an upper portion ofthe light emitting element 204 and a portion on the electricallyconductive member 202 c which serves as an electrode (not shown). Thoseothers than as described above are carried out as in the same manner asthat in the first embodiment.

<Filler-Applying Step>

As shown in FIG. 11(a), the filler applying step includes, among thesurfaces of the metal member 103 on the electrically conductive members202 a, 202 b, 202 c, applying a filler 114 to cover the portions wherethe light emitting element 204 is not disposed, by using an electrolyticplating technique, an electrodeposition coating technique, or anelectrostatic coating technique. In this step, after the light emittingelements 204 are bonded, the surfaces of the metal member 103respectively formed on the electrically conductive members 202 a, 202 b,202 c, and electrically conductive portions of other members are coveredwith the filler 114. Also, the surfaces such as the electricallyconductive portions of the light emitting elements 204 and the lowersurface of the wires 206 are preferably covered with the filler 114.Those others than as described above are carried out as in the samemanner as that in the first embodiment.

<Light-Blocking Member Forming Step>

As shown in FIG. 11(b), a light-blocking member forming step includesforming a light blocking member 207 in the recess 209 b, 209 c of thebase member 201 to cover the filler 114. This step is for covering theexposed portions of the base member 201 which are exposed on the sidesurfaces 230 a, 230 b, 230 c of the recesses 209 b, 209 c with the lightblocking member 207. Moreover, the light blocking member may be formedto cover entire exposed portions of the side surface 230 a of the recess209. Covering those regions with the light blocking member 207 enables,as described above, to prevent optical loss caused by passing of lightfrom the exposed portions of the base member 201. The light blockingmember 207 may be omitted according to the configuration or combinationof other members. A resin is preferably used for such a light blockingmember 207, and may be formed by using a potting technique, a printingtechnique, or the like.

<Light Transmissive Member Forming Step>

As shown in FIG. 12, in the light transmissive member forming stepincludes forming a light transmissive member 108 on the base member 201and covering the light emitting elements 204 with the light transmissivemember 108. That is, in this step, the light transmissive member 108 forcovering the light emitting elements 204, wires 206, or the like, isformed in the recess 209 a of the base member 201 and cured. The lighttransmissive member forming step is performed in the same manner as thatdescribed in the first embodiment except that, in the case where a lightblocking member (for example, a resin capable of reflecting light of anemission wavelength) 207 is formed, the light transmissive member 108 isformed in the recess 209 a of the base member 201 after the lightblocking member 207 is formed.

Third Embodiment

A light emitting device which uses a FD element will be described in athird embodiment. First, a general construction of a light emittingdevice will be described with description of each component, then, thematerial or the like of each member will be described. In what follows,the different points from the above embodiment of the light emittingdevice 100 will be mainly described.

<General Construction>

As shown in FIG. 14 and FIG. 15, the light emitting device 100 includesa light emitting element 104 having a semiconductor layer 11 and atransparent substrate 10, a reflective member 114 applied so that atleast a portion of a side surface and the upper surface of thetransparent substrate 10 are exposed and a side surface of thesemiconductor layer 11 is covered therewith, and the light transmissivemember 108 which covers the portions of the transparent substrate 10exposed from the reflective member 114.

In the present embodiment, as shown in FIG. 14 and FIG. 15, the lightemitting device 100 has at least one light emitting element 104 (one isshown in the figures), and mainly equipped with a base member 101 havinga recess 109, electrically conductive members 102 a, 102 b disposed onthe bottom surface of the recess 109, the electrically conductive member102 b disposed on the side surfaces of the recess 109, a light emittingelement 104 mounted on the bottom surface of the recess 109, areflective member (in the embodiment, an insulating filler 114 is used)covering at least a portion of the surfaces of the electricallyconductive members 102 a, 102 b which do not have the light emittingelement mounted thereon, and a light transmissive member 108 coveringthe light emitting element 104. Further, in this case, a protectiveelement 105 and a wire 106 are disposed.

(Base Member)

As shown in FIG. 15(a), the base member 101 has a recess 109 which opensupward, and the bottom surface 120 and the side surface 130 are formedby the recess 109. The electrically conductive members 102 a, 102 b aredisposed on the bottom surface 120 of the recess 109, and theelectrically conductive member 102 b is disposed on the side surfaces ofthe recess 109.

Also, the light emitting element 104, the conductive wire 106, and thelike, are disposed in the recess 109. Accordingly, the recess 109 isneeded to have a size which allows directly mounting the light emittingelement by using a die-bonding equipment or the like, and which allowsestablishing of electrical connection with the light emitting element byusing such as wire-bonding, but the shape of the recess 109 is notspecifically limited. Examples of the shape the opening of the recessinclude, when viewed from the opening side, an approximately quadrangleshape and a circular shape. Also, the angle of the side surfaces 130 isnot specifically limited. For example, the side surfaces may be taperedto a wider dimension toward the opening, may have a paraboloidalsurface, or may be configured approximately perpendicular to the bottomsurface 120.

(Electrically Conductive Member)

As shown in FIG. 15(a), the electrically conductive member disposed onthe side surfaces (side walls) 130 of the recess 109 may be such that,one of the electrically conductive members 102 a, 102 b is extended tothe side surfaces (side walls) 130 in the recess 109, or otherelectrically conductive member is disposed. That is, the electricallyconductive members 102 a and 102 b disposed on the bottom surface 120are generally to function as electrodes, but the electrically conductivemember disposed on the side surface 130 may not necessarily serves as anelectrode.

The electrically conductive member 102 a is disposed in an island shapeon the bottom surface 120 of the base member 101, and the electricallyconductive member 102 b is disposed so that the peripheral portion ofthe electrically conductive member 120 a and the side surfaces 130 arecovered in continuous manner. That is, in the light emitting deviceaccording to the present embodiment, the electrically conductive member102 b disposed on the side surfaces 102 b have negative polarity.

According to the light emitting device of the present invention, theelectrically conductive member is disposed on the side surfaces 130 ofthe recess 109, so that using a technique such as electrodepositioncoating, the filler 114 can be disposed on the side surfaces of therecess 109 uniformly and with a high density. Also, disposing theelectrically conductive member on the side surfaces enables to preventlight from leaking out from the side surfaces of the recess.

(Filler)

Moreover, the filler 114 is also disposed on the surface of theelectrically conductive members 102 b disposed on the side surfaces 130of the recess 109. The exposed portions of the semiconductor layer 11 ofthe light emitting element 104 and the side surfaces of the bondingmember 111, and the groove (G) of the slit in the conductive portion arecovered with the filler 114.

As shown in FIG. 15(a), in the case where the electrically conductivemember 102 b is disposed to the top edge portion of the side surfaces130 of the recess 109, with using electrodeposition coating techniquewhich to be described later, the filler 114 can be disposed to cover theelectrically conductive members 102 b which are exposed at the uppersurface of the base member. Moreover, when the light transmissive member108 is filled, the light transmissive member is impregnated in thefiller 114 locates at the upper surface of the base material. The filler114 and the light transmissive member 108 bulging out on the uppersurface as described can be left as they are, or the upper surface ofthe base member 101 can be polished so that the light transmissivemember 108 and the filler 114 are not bulging out from the uppermostsurface of the base member 101. Also, as shown in FIG. 15(b), asdescribed in the first embodiment, the protective element 105 is alsocovered with the filler 114.

«Method of Manufacturing Light Emitting Device»

Next, a method of manufacturing the light emitting device according to athird embodiment of the present invention will be described. One methodof manufacturing a light emitting device 100 according to the presentinvention includes an electrically conductive member forming step, adie-bonding step, a filler applying step, and a light transmissivemember forming step. In the first embodiment, the metal member 103 andthe protective element 105 are disposed, so that a metal member formingstep, a protective element joying step, and a wire-bonding step areincluded. In what follows, the different points from the method ofmanufacturing of first embodiment will be mainly described.

In this embodiment, a electrically conductive member is disposed on thebottom surface and the side surfaces of the recess and the lightemitting element 104 is mounted on the bottom surface of the recess. Inthe metal member forming step, a technique such as plating technique,sputtering technique, vapor deposition technique, or a technique ofbonding a thin film, can be used. Also, in the filler-applying step,among the surfaces of the electrically conductive members 102 a, 102 b,the portions which do not have the light emitting element 104 mounted,including the side surfaces 130 of the recess 109, are covered with thefiller 114. Those others than as described above are carried out as inthe same manner as that in the first embodiment, description thereofwill be omitted below.

Next, SEM images of the light emitting device 100 of the thirdembodiment will be shown in FIG. 30, FIG. 31. FIGS. 31(a), 31(b) arepartially-enlarged views of the areas indicated as a1, a2 in FIG. 30,respectively. Here, FIG. 30 is a secondary electron image and FIG. 31 isa reflection electron image. As shown in FIG. 30, FIG. 31, at least aportion of the side surfaces and the upper surface of the transparentsubstrate 10 are exposed, and the side surfaces of the semiconductorlayer 11 are covered with the reflective member (filler) 114. In theimage, “KT” indicates a fluorescent material.

Fourth Embodiment

A light emitting device which uses a FU element will be described in afourth embodiment. FIG. 18(a) shows a perspective view of an example ofa light emitting device according to the present embodiment. First, ageneral construction of a light emitting device will be described withdescription of each component, then, the material or the like of eachmember will be described. In what follows, the different points from theabove embodiment of the light emitting device 200 will be mainlydescribed. Though, the metal member 103 and the bonding member 111 arenot shown in the figures illustrating a light emitting device 200 of thefourth embodiment.

<General Construction>

As shown in FIG. 18 and FIG. 19, a light emitting device 200 is a devicein which at least one light emitting element 204 (two in the figures)are mounted, and mainly includes a base member 201, electricallyconductive members 202 a, 202 b, 202 c which are disposed on the basemember 201, light emitting elements 204 mounted on the respectiveportions of the electrically conductive members 202 a, 202 b, 202 c, awire 206 which connects a portion of the electrically conductive member202, which serves as an electrode, with an electrode terminal of thelight emitting element 204, insulating filler 114 which covers theelectrically conductive members which do not have the light emittingelement 204 mounted thereon, and a lower surface of the wire 206, and alight transmissive member 108 which covers the light emitting element204 and the filler 114.

(Base Member)

As shown in FIG. 19, the base member 201 has a recess 209 which opensupward, and the bottom surface 220 and the side surface 230 are formedby the recess 209. The electrically conductive member 202 a, theelectrically conductive member 202 b, and the electrically conductivemember 202 c are disposed on the bottom surface 220 of the recess 209.Also, the electrically conductive member 202 d is disposed on the sidesurfaces 230 of the recess 209.

(Electrically Conductive Member)

As shown in FIG. 19, the electrically conductive members 202 a, 202 bare also disposed on the back surface of the base member 201 so as to berespectively electrically connected to the electrically conductivemembers 202 a, 202 b (respectively to be an electrically single member)in the base member 202. Moreover, the electrically conductive member 202c does not serve as an electrode, and is spaced apart from the bottomsurface 220 and covers the side surfaces of the recess 209.

(Filler)

As shown in FIG. 19, among the surfaces of the metal member on theelectrically conductive members 202 a, 202 b,202 c disposed on thebottom surface 220 of the recess 209, the portions which do not have thelight emitting element 204 mounted thereon are covered with the filler114. Moreover, the electrically conductive member 202 d disposed on theside surfaces 230 of the recess 209 is also covered with the filler 114.Further, the filler 114 covers the entire surface of the wire 206, andalso covers the peripheral region of the light emitting elements 204 andalso the side surfaces of the joining layer 123 under the light emittingelements 204. That is, of the portions of the electrically conductivemembers 202 a, 202 b, 202 c, other than the regions where the lightemitting elements 204 are mounted, are covered with the filler 114.

«Method of Manufacturing Light Emitting Device»

Next, a method of manufacturing the light emitting device according to afourth embodiment of the present invention will be described. One methodof manufacturing a light emitting device 200 according to the presentinvention includes a step of forming electrically conductive members, astep of die-bonding, a step of applying filler coating, and a step offorming a light transmissive member. In the fourth embodiment, a FUelement is used, so that a wire-bonding step is included. In whatfollows, the different points from the method of manufacturing of thesecond embodiment will be mainly described.

In the step of forming a electrically conductive member, theelectrically conductive members 202 a, 202 b, 202 c, and 202 d areformed on the base member 201. In the step of forming a metal member,the metal member is formed on the electrically conductive members 202 a,202 b, and 202 c on the base member 201. In the case where the metalmember is also formed on the electrically conductive members 202 a, 202b which are on the back surface 240 of the base member 201, they areformed in this step. In the die-bonding step, the light emitting element204 is mounted through the bonding member 111 on the metal member on thebottom surface 220 of the recess 209 of the base member 201. In the stepof wire-bonding, a portion on the electrically conductive member 202 awhich serves as an electrode and an electrode terminal (pad electrode)at an upper portion of the light emitting element 204 are electricallyconnected by a wire 206. In the same manner, in this step, the electrodeterminal (pad electrode) on the light emitting element 204 and a portionon the electrically conductive members 202 b, 202 c which serve aselectrodes are respectively electrically connected by wires 206.

In the step of applying filler coating, among the surfaces on theelectrically conductive members 202 a, 202 b, 202 c, 202 d, the portionswhich do not have the light emitting element 204 mounted thereon arecovered with the filler 114. According to this step, after the lightemitting element 204 were bonded, the surfaces of the electricallyconductive members 202 a, 202 b, 202 c, 202 d, and the conductiveportions of other members are covered with the filler 114. Also, thesurfaces such as the conductive portions of the light emitting elements204 and the surface of the wire 206 are preferably covered with thefiller 114. Also, it may be such that, the surfaces of the electricallyconductive members are covered with the metal member and the filler 114covering is applied thereon. Those others than as described above arecarried out as in the same manner as that in the first embodiment andthe second embodiment, description thereof will be omitted below.

«Other Variant Examples of Third, and Fourth Embodiments»

As an example of other variant examples of the third and the fourthembodiments, a construction will be described below, in which, the upperend portion of the recess of the base member has a region on which aelectrically conductive member is not disposed. For example, in thethird embodiment and the fourth embodiment, examples in which theelectrically conductive member is disposed on the entire side surfacesof the recesses 109, 209 are described, but the electrically conductivemember may not be disposed on a portion of the side surfaces of the sidesurfaces 130, 230 of the recesses.

Particularly, on the side surfaces of the recess, a portion abutting onthe top edge surface of the recesses 109, 209 preferably has a region onwhich the electrically conductive member is not disposed. With thisarrangement, at the time of such as electrodeposition coating,deposition of the filler on the upper surface of the base members 101,201 can be prevented, so that it can be prevented from becoming a causeof irregularity in height. In the case where the filler is disposed onthe upper surface of the base member 101, 201, at the time of fillingthe light transmissive member 108 in the recess, the light transmissivemember may be impregnated in the filler, which may result in the resinbulging out on the upper surface of the base member. Particularly, aresin which has tack properties such as a silicone resin may causetroubles in which, for example, the light emitting devices sticktogether, or foreign substances may be attached on the resin bulged onthe upper surface of the base member during the manufacturing steps.Therefore, it is preferable that the resin is not disposed on the uppersurface of the base member.

Further, it is preferable that at the top edge surface side of therecess, a step is formed at the side surface of the recess 130, 230 andthe side surface of the step has a region where the electricallyconductive member is not formed. Next, an example will be described inwhich a step is disposed in the third embodiment.

In the light emitting device 100 of FIG. 16, at the top edge surfaceside of the recess 109, a step 150 is formed on the side surfaces 130 ofthe recess 109, and the side surfaces 160 of the step 150 have a regionwhere the electrically conductive member 102 b is not formed. Asdescribed above, the electrically conductive member is formed on thebottom surface 170 of the steps while a region where the electricallyconductive member is not formed is formed at the upper end portions ofthe recess 109. Thus, the filler covering can be applied also near theupper end portion of the recess 109. The filler for covering theelectrically conductive member is disposed on the step 150, and thus thefiller 114 and the light transmissive member 108 can be prevented frombulging out from the upper surface of the base member 101.

At this time, the shortest distance between the bottom surface 170 ofthe step and the surface of the light transmissive member 180 ispreferably ⅕ or less with respect to the height of the recess 109. Ifthe distance between the bottom surface 170 of the step and the top edgesurface of the recess 109 is large, the region where the electricallyconductive member is not formed increases. Here, the filler 114 is notformed on the region where the electrically conductive member is notformed, so that the light irradiated on the side surface 160 of the stepis absorbed in the base member 101. Particularly, an electricallyconductive member having a low reflectance such as tungsten is typicallyused for the interface between the electrically conductive member andthe base member in terms of adhesion, so that leaked light into the basemember reflects diffusely in the base member and absorbed in theelectrically conductive member which has a low reflectance.

For this reason, the side surface 160 of the step is arranged so that aslittle as light is irradiated thereon. Light propagates in the lighttransmissive member 180, so that in the recess 109, from the portionwhere the light emitting element 104 is mounted to the portion on theside surface 160 of the step is formed narrower to narrow the pathway oflight. With this arrangement, even if the amount of filled lighttransmissive member is increased, leakage of light can be reduced tominimum. Here, as shown in FIG. 16, the shortest distance K1 between thebottom surface 170 of the step and the surface of the light transmissivemember 180 is ⅕ or less with respect to the height K3 of the recess 109.With this arrangement, little light is allowed to propagate to outside.Here, over the bottom surface 170 of the step, a distance K2 which isthe thickness of the electrically conductive member 102 b (in somecases, further with a metal member) plus the thickness of deposition ofthe filler 114 is set. The smaller the K1−K2, the less light propagatesto the outside, so that is preferable, and K1=K2 is more preferable.Further, K2 is preferably set so that it is not higher than the uppersurface. Also, the surface of the light transmissive member 108preferably has a recessed shape. With the recessed shape, the uppersurface of the resin will not become higher than the upper surface ofthe base member 101 or 201, so that problems such as sticking of thelight emitting devices with each other can be avoided.

In FIG. 17(a), the shape of the electrically conductive member of thelight emitting device shown in FIG. 16 is changed, and other portionsare the same as in FIG. 16. In the light emitting device 100, anelectrically conductive member is disposed on a portion of the bottomsurface of the step 150. In other words, the bottom surface of the stephas a region where the upper surface of the electrically conductivemember is exposed, and a region where the electrically conductive memberis not exposed. In addition, through the bonding member 111, the lightemitting element 104 is mounted in a bridged manner on the electricallyconductive members 102 a and 102 b formed on the bottom surface of therecess. Further, on the side surfaces of the recess, the electricallyconductive member 102 c is formed so as to be spaced apart from theelectrically conductive members 102 a, 102 b at the bottom surface. Theelectrically conductive member on the side surfaces may be formed byusing any technique, for example, by using a metalization technique.

Also in FIG. 17(a), the shape of the electrically conductive members ofthe light emitting device shown in FIG. 16 is changed, and otherportions are the same as in FIG. 16.

In the light emitting device 100, an electrically conductive member isnot formed below the electrically conductive member 102 d formed on theside surfaces, so that electrical insulation with respect to theelectrically conductive members formed on the bottom surface of therecess can be maintained. For example, a base material made of aco-fired ceramics may be used.

«Other Variant Examples»

For example, the base members 101, 201 having a recess 109 or recesses209, 209 a, 209 b, 209 c are illustrated, but in other variant examples,a planar base member which does not have the recess 109 or recesses 209,209 a, 209 b, 209 c may be used. In such case, the light transmissivemember 108 is sufficient to be deposited on the upper surface of theplanar base member. Further, in this case, a configuration in which thelight transmissive member 108 is not disposed may be employed.

In the first and the third embodiment, a protective element 105 isprovided, but in the second and the fourth embodiments, a constructionhaving a protective element may have employed, and further, in the firstto the fourth embodiments, a protective element such as a Zener diodemay be disposed. Further, in the first to fourth embodiments,constructions having one or two light emitting elements 104, 104 (204,204) are disposed, but respectively, three or more of the light emittingelements may be disposed. Also, in the case where two or more ofplurality of the light emitting elements are provided to a single lightemitting device, each of the light emitting element may have a differentemission wavelength. For example, a light emitting device may have threelight emitting elements respectively emitting three primary colors ofRGB.

In the light emitting device 200, the width of the joining layer 123(reflective layer 22 a, barrier layer 22 b, and adhesion layer 22 c)disposed at the lower surface side of the light emitting element 204 issmaller than the width of the light emitting element 204, however, thepresent invention is not limited thereto. For example, the width of thejoining layer 123 disposed at the lower surface side of the lightemitting element 204 and the width of the light emitting element 204 maybe modified to the same. This facilitates covering of the side surfacesof the joining layer 123 with the filler 114.

In addition, the light emitting device 100 (200) according to theembodiments described above has a light emitting element 104 (204)capable of emitting light of visible region, but a construction having alight emitting element capable of emitting ultraviolet light or infraredlight may be employed. Further, in the present embodiment, the lighttransmissive member 108 is filled to cover (seal) the whole recess, butthe light transmissive member 108 may be applied to cover each singlelight emitting element 104 (204) or to cover a plurality of lightemitting elements at once.

In the method of manufacturing light emitting device, for performing thepresent invention, a step other that those as described above may beincluded between or before or after each of the steps in a manner thatdoes not adversely affect each of the steps. For example, other stepssuch as a step of washing base member in which the base member 101 or201 is washed, a step of removing undesired substances such as dust, anda step of adjusting mounting position in which the mounting position ofthe light emitting element 104, 204 or the protective element 105 isadjusted. The variant examples described above may be used appropriatelyin accordance with the five and the sixth embodiments to be describedlater and their variant examples.

Next, as those embodiments which do not use the base member, the fifthand sixth embodiments will be described and then variant examplesaccording to the fifth and sixth embodiments will be described. Thelight emitting device according to those embodiments will be indicatedby reference numerals 100A to 300A. In what follows, the differentpoints from that in the first to fourth embodiments will be mainlydescribed.

Fifth Embodiment

FIG. 20 is a schematic cross-sectional view showing a light emittingdevice according to a fifth embodiment of the present invention.

<Structure of Manufacturing Light Emitting Device>

In the present embodiment, a light emitting device 100A includes a lightemitting element 104A having electrodes 104 c disposed on the surface ofthe semiconductor layer 104 b, electrically conductive members 102respectively connected to corresponding electrodes 104 c of the lightemitting element 104A, a reflective member 114 covering peripheralportions of the electrodes 104 c of the light emitting element 104A andthe electrically conductive members 102, and a light transmissive member108 covering an upper surface which is opposite to the surface where theelectrodes 104 c are disposed, and the side surfaces of the lightemitting element 104A.

The light emitting element 104A includes a semiconductor layer 104 bformed on one main surface of a transparent substrate 104 a which has apair of main surfaces at opposite sides. Moreover, the positiveelectrode and negative electrode (hereinafter may be referred to aselectrodes) are formed on the surface of the semiconductor layer 104 b.In the light emitting device 100A of the present invention, the lightemitting element 104A is disposed so that the transparent substrate 104a side, which is opposite side to the electrodes forming surface. Morespecifically, in the light emitting element 100A shown in FIG. 20, theupper surface of the transparent substrate 104 a serves as the uppersurface of the light emitting element 104A. On the lower surface of thetransparent substrate 104 a, the semiconductor layer 104 b whichincludes a first semiconductor layer, an active layer, and a secondsemiconductor surface in this order is stacked. The negative electrodeor the positive electrode is disposed on the first semiconductor layeror the second semiconductor layer, respectively. The electrodes 104 c ofthe light emitting element 100A are preferably formed with a metal withhigh reflectivity, and for example, the electrodes containing Ag or Alare suitable. With this arrangement, light from the light emittingelement 104A can be reflected at the electrodes 104 c and extracted fromthe transparent substrate side 104 a.

The electrically conductive members 102 are, for example, formed byusing plating, and adhered respectively to the positive electrode ornegative electrode of the light emitting element 104A through anelectrically conductive die-bonding member 111. The electricallyconductive members 102 are respectively connected to the light emittingelement 104A and serve as the electrode terminals of the light emittingdevice 100A. The lower surface of the electrically conductive members102 are exposed outside and constitute a portion of the outer surface ofthe light emitting device 100A.

The reflective member 114 has insulating property and covers at leastthe sides surfaces of the conductive portions such as the electricallyconductive members 102 and die-bonding members 111. In the presentembodiment, the reflective member 114 further covers the side surfacesof the electrodes 104 c of the light emitting element 104A. Further, thereflective member 114 is extendedly disposed at the lower portion so asto be exposed at the side surfaces of the light emitting device 100A.

The light transmissive member 108 is disposed on the light emittingelement 104A and the reflective member 114 which is disposed on theperipheral area of the light emitting element 104A. The lighttransmissive member 108 may contain a fluorescent material or the like.In the present embodiment, the light transmissive member 108 covers theupper surface and side surfaces of the transparent substrate 104 a andthe side surfaces of the semiconductor layer 104 b of the light emittingelement 104A. The interface between the light transmissive member 108and the reflective member 114 is disposed approximately the same heightas or higher than the interface between the electrodes 104 c and thesemiconductor layers 104 b.

As described above, in the light emitting device 100A according to thepresent embodiment, the side surfaces of the electrically conductivemembers 102 and the die-bonding members 111 are covered with thereflective member 114. With such arrangements, optical loss due to lightfrom the light emitting element 104 a entering the electricallyconductive members 102 and die-bonding members 111 can be reduced. Asshown in FIG. 20, it is preferable that approximately entire surface ofthe lower surface of the light transmissive member 108 is covered withthe reflective member 114. The light propagating downwardly from thelight emitting element 104A is reflected by the reflective members 114having high reflectance or the electrodes 104 c, thus light can beextracted efficiently. Also, generally, in a light source using a lightemitting element and a wavelength converting member, the light emittingelement is mounted on a package made of a ceramics or a resin, and then,a wavelength converting member is disposed. But disposing the lightemitting device according to the present invention to various packagesenables selecting of the color prior to mounting to such packages, sothat yield after mounting increases.

«Method of Manufacturing Light Emitting Device»

A method of manufacturing a light emitting device according to thepresent invention will be described below. FIGS. 21 through 24 areschematic cross-sectional views showing steps of manufacturing a lightemitting device according to the present embodiment. A method ofmanufacturing a light emitting device according to the presentembodiment mainly includes a step (first step) of bonding electrodes 104c of a plurality of light emitting elements 104A on a support substrate101 and a step (second step) of disposing a reflective member 114 on thesupport substrate 101 to a height so that at least peripheral portionsof the electrodes 104 c of the light emitting elements 104A are covered,by using an electrolytic plating technique, an electrodeposition coatingtechnique, or an electrostatic coating technique. Further, the presentembodiment includes a step (third step) of forming a light transmissivemember 108 on the reflective member 114 to cover an upper surface andside surfaces of the light emitting elements 104A, and a step (fourthstep) of removing the support substrate 101 and dividing the reflectivemember 114 and the light transmissive member 108 to individuallyseparating the light emitting elements 104A.

<First Step>

First, the support substrate 101 is prepared. The support substrate 101is a plate-shaped or a sheet-shaped member and serves to hold the lightemitting device in the steps of manufacturing light emitting deviceaccording to the present embodiment. The support substrate 101 isremoved prior to individually dividing the light emitting devices, sothat it is not included in the light emitting device.

The support substrate 101 is preferably a substrate which has electricalconductivity. For the support substrate 101, a single layer or stackedlayers of metal or alloy can be used. The support substrate 101 may beformed with a stacked layer of resin and metal. Examples of the metalused for the support substrate 101 include SUS and Cu.

On the support substrate 101, a photosensitive resist is attached as aprotective film. Over that, a photomask having a predetermined patternis directly or indirectly arranged, and ultraviolet light is used toexpose. Then, photo processing is performed to form a resist having aplurality of openings which are spaced apart from each other. In a casewhere the protective film (resist) is formed by using photolithography,the protective film (resist) may either be of positive type or negativetype.

Then in the openings of the resist, a electrically conductive members102 are selectively disposed. The electrically conductive members 102are preferably formed with a thickness of 0.1 to 500 μm. Theelectrically conductive members 102 are preferably formed by using anelectrolytic technique. The materials, stacked structure, conditions orthe like of plating can be appropriately adjusted by using a knowntechnique in the art. After the electrically conductive members 102 areformed, the resist, which is a protective film, is removed. Thus, theelectrically conductive members 102 which are spaced apart from eachother are formed.

Next, on the respective electrically conductive members 102, the lightemitting elements 104A are respectively bonded by using a die-bondingmember 111. Examples of the die-bonding member include a solder materialsuch as Au—Sn, a metal bump such as Au. The die-bonding member 111 maybe formed interposing between the electrically conductive members 102and the corresponding light emitting element 104A. For this, thedie-bonding member 111 may be disposed: (A) on the electricallyconductive member 102 side; (B) on the electrode 104 c side of the lightemitting element 104A; or (C) on the both the electrically conductivemembers 102 and the electrode 104 c of the light emitting element 104A.

The bonding member 111 in a form of paste or a sold (a sheet, a brick,or powder) can be used, and which can be appropriately selectedaccording to the composition of the die-bonding member 111, the shape ofthe electrically conductive members 102, or the like.

Here, a bonding method will be described in the case of the portionwhere the die-bonding member 111 is to be formed is at the electricallyconductive member 102 side as in the above-described (A) and a pastesolder material is used as the die-bonding member 111. First, on theelectrically conductive members 102, a paste solder material 111 isdisposed. The technique of disposing the solder material 111 may beappropriately selected from dispensing, printing, plating,electrocoating, electrostatic coating, etc. Then, the electrodes 104 cof the light emitting element 104A are adhered to the portions where thesolder material 111 is disposed. Thereafter, the temperature is raisedto where the solder material 111 melts and maintained for a given lengthof time, then lowered to the room temperature. Then, flux or the like,remaining around the solder material 111 is removed by washing.

<Second Step>

Next, an insulating reflective member 114 is disposed to cover theelectrically conductive members 102 exposed in the first step and theconductive portion of the die-bonding member 111 etc. FIG. 22(b) shows acompleted state of the second step.

By covering the exposed portions of the electrically conductive members102 and the conductive portion of the die-bonding member 111 etc. withthe reflective member 114, optical loss caused by entering light tothose portions can be reduced. Therefore, in the second step, thereflective member 114 is preferably formed to cover the region of atleast 40% of the area of the whole area of the electrically conductivemembers exposed. Further, among the exposed regions of the conductiveportions in this stage, approximately the entire area is preferablycovered with the reflective member 114. Here, the term “exposed region”refers to a region which is visible from outside except for a region onthe surface of the light emitting element 104A where insulatingprotective film is applied. The reflective member 114 is preferablyformed on the support substrate 101 to a height that covers theperiphery of the electrodes 104 c of the light emitting element 104A. Inthe present embodiment, the reflective member 114 is formed to a heightthat covers the side surfaces of the semiconductor layer 104 b of thelight emitting element 104A.

For the technique of forming the filler 114, an electrolytic platingtechnique, an electrostatic coating technique, or an electrodepositioncoating technique can be used. Using those techniques, for example, thereflective member 114 can be deposited efficiently and selectively withrespect to the conductive portions such as the electrically conductivemembers 102 and the die-bonding members 102. In addition, in order tohold the reflective member 114, a binder such as a resin or an inorganicmaterial may be added or impregnated to the reflective member 114 whichis disposed. Also, the light transmissive member 108, which is used inthe third step to be described later, may be impregnated in thereflective member 114.

<Third Step>

Next, the light transmissive member 108 for covering the light emittingelement 104A is formed and cured. FIG. 23(a) is a diagram illustratingthe light transmissive member 108 is formed on the reflective member 114and covers the light emitting element 104A. The light transmissivemember 108 is preferably formed to a height that covers the uppersurface and the side surfaces of the light emitting element 104A exposedfrom the reflective member 114. For the technique of forming the lighttransmissive member 108, potting, printing, compression molding,transfer molding, thermal spraying, electrocoating, casting,spin-coating, etc., can be used. The light transmissive member 108formed in this way can be cured by heating or optical irradiation. Thelight transmissive member 108 can be made of a single member, or madewith two or more of a plurality of layers.

In the case where the light transmissive member 108 is cured by heating,the time of raising or lowering the temperature, and atmosphere etc. canbe appropriately selected. In the case where the light transmissivemember 108 is cured by optical irradiation, the irradiation time and thewavelength of the irradiating light can be appropriately selectedaccording to the materials to be used. The light transmissive member 108may be cured by using the both heating and optical irradiation.

Also, a coloring agent, a light diffusing agent, filler, a wavelengthconverting member (fluorescent member), or the like, may be contained inthe light transmissive member 108. The thickness of the lighttransmissive member 108 may be adjusted by polishing etc., or a lensshape inclusive of a microlens array or formation of irregular surfaceetc., an optical function of controlling the optical alignment can beprovided to the light transmissive member 108.

<Fourth Step>

After the third step, the support substrate 101 is removed. With this,the bottom surface of the electrically conductive members 102 areexposed. FIG. 23(b) is a diagram illustrating a state in which thesupport substrate 101 is removed. For the technique of removing thesupport substrate 101, physical removing or selective removing of thesupport substrate 101 with a use of etching etc., can be used.

The dicing sheet 112 is attached to the obtained aggregate of the lightemitting devices (FIG. 24(a)). Thereafter, at the dividing portions 118as shown in 24(b), that is, performing cutting at a positions capable ofdividing the reflective member 114 and the light transmissive member 108between the light emitting elements 104A, to obtain individual lightemitting elements 104A, thus to obtain the light emitting devices 100Aas shown in FIG. 20. Various known methods can be employed forseparating the individual devices, such as a dicing method using a bladeand a dicing method using a laser beam. FIG. 24(b) illustrates a statewhere the light emitting elements 104A are individually divided, butaccording to the purpose, but dividing to obtain an array or anaggregate of a group of two or four light emitting elements 104A may beperformed.

Hereinafter, each constructional member of the light emitting devicewill be described in detail. Also, descriptions of like portions as inthe first to fourth embodiments will be appropriately omitted.

(Light Emitting Element)

The light emitting elements used in the present embodiment arepreferably made by stacking semiconductor materials on a transparentsubstrate and divided into individual chips. For the materials of thesubstrate for stacking nitride semiconductors, for example, aninsulating substrate such as sapphire or spinel, or an electricallyconductive substrate such as GaN, SiC, Si, ZnO or the like can bepreferably used.

For the material suitable for the positive electrode and negativeelectrode, any material having electric conductivity may be suitablyused, for example, one of the metals among Au, Pt, Pd, Rh, Ni, W, Mo,Cr, Ti, Ag, and Al, or an alloy of those, or a combination of those, maybe used. Particularly, Ag or Al, which has high reflectance ispreferably contained. Forming the electrodes using a metal having highreflectance allows the light blocked by the electrodes to be reflectedand extracted from the substrate side, so that the light extractionefficiency of the light emitting device can be improved, and thuspreferable. Also, an insulating protective film may be formed onsubstantially the entire surfaces of the light emitting element exceptfor the surfaces of the electrodes which serve as connection regionswith the electrically conductive members or the die-bonding members. Forthe protective film, SiO₂, TiO₂, Al₂O₃, a polyimide can be used.

The emission wavelength of the light emitting element can be variouslyselected according to the materials and the content ratio of the mixedcrystal of the semiconductor layer. In the case where the light emittingdevice includes a light transmissive member containing a fluorescentmaterial, the semiconductor used for the light emitting layer ispreferably a nitride semiconductor (In_(X)Al_(Y)Ga_(1-X-Y)N, 0.X, 0.Y,X+Y.1) capable of emitting light of short wavelength.

A light emitting element capable of emitting ultraviolet light orinfrared light can also be employed as well as a light emitting elementcapable of emitting visible light. Further, a protective element such asa Zener diode or a light receiving element or the like can be mountedwith the light emitting element.

(Electrically Conductive Member)

The electrically conductive member is attached to the positive electrodeand the negative electrode of the light emitting element and serve asthe electrodes of the light emitting element which are electricallyconnected to the respective external electrodes. On at least oneelectrically conductive members, the positive electrode of the lightemitting element is disposed directly or through the die-bonding memberetc. Also, on at least one electrically conductive members, the negativeelectrode of the light emitting element is disposed directly or throughthe die-bonding member etc.

In the case where a material easily detached from the support substrateor where the support substrate is removed by using etching, theelectrically conductive members are needed to be made of a materialhaving a selectivity to the solution and is disposed at a portion whichis in contact with the support substrate. More specifically, a noblemetal such as Au, Pt, Rh, Ir, and Pd or an alloy of those is preferable.Moreover, a film of another metal may be formed thereon. Morespecifically, Ni, Cu, Ag, Cr, W etc. can be used. The electricallyconductive members preferably have a thickness of about 0.1 μm to 500μm.

Each of the electrically conductive members has, for example, an uppersurface on which the electrode of the light emitting element isdisposed, and a lower surface which forms an outer surface of the lightemitting device. The upper surface of the electrically conductivemembers has a size larger than the area capable of disposing theelectrode of the light emitting element. The lower surface of theelectrically conductive members is exposed to outside without beingcovered with the reflective member etc. The side surfaces of theelectrically conductive members may be flat, or may have minuteirregularity. Also, the side surfaces of the electrically conductivemembers may have a shape with a slant or curve at the lower surfaceside. With this arrangement, detachment between the reflective memberand the electrically conductive members can be prevented.

(Die-Bonding Member)

A die-bonding member is preferably used for adhering the electricallyconductive members with the electrodes of the light emitting element.Using a die-bonding member having electric conductivity enables toelectrically connect the electrically conductive members and the lightemitting element. Examples of the die-bonding member include a soldermaterial such as Au—Sn, a metal bump such as Au. Particularly, amaterial having a high melt point such as Au—Sn is preferably used. Thethickness of the die-bonding member is preferably about 0.5 μm to 500μm.

(Reflective Member)

The reflective member has an insulating property, and is disposed tocover mainly the side surfaces of the electrically conductive members.In the case where the electrically conductive members are adhered to theelectrodes of the light emitting element through a die-bonding member,the reflective member is preferably disposed to also cover the sidesurfaces of the die-bonding member. The reflective member serves toreflect the light emitted from the light emitting element or the lightwhose wavelength is converted by a wavelength converting member. Thus,optical loss due to the light entering the electrically conductivemembers can be reduced. The reflective member is preferably disposed tocover the surround of the electrodes of the light emitting element. Alsoat the lower surface of the light emitting device, the reflective memberis disposed at a portion which does not have an electrically conductivemember disposed thereon. The provision of such reflective member enablesto prevent light of the light emitting element from leaking out from thelower surface of the light emitting device, so that the light extractionefficiency in an upper surface direction can be improved. The reflectivemember preferably has a reflectance of 50% or more with respect to thelight in the wavelength range of 430 nm to 490 nm (blue light). Thefiller having a particle size in the range of 10 nm to 10 μm ispreferably used. Further preferably the thickness is in a range of about100 nm to 5 μm. With this arrangement, good scattering of light can beachieved.

(Light Transmissive Member)

The light transmissive member covers the upper surface and the sidesurfaces of the light emitting element. The interface between the lighttransmissive member and the reflective member is placed at the lightemitting element side. The thickness from the upper surface of the lightemitting element to the upper surface of the light transmissive memberis preferably approximately the same as the thickness from the sidesurfaces of the light emitting element to the side surfaces of the lighttransmissive member. Thus, good optical distribution can be obtained inthe near-field, and uniform emission can be obtained in variousdirections at the light emitting surface of the light emitting element.Alternatively, the thickness from the side surfaces of the lightemitting element to the side surfaces of the light transmissive membermay be smaller than the thickness from the upper surface of the lightemitting element to the upper surface of the light transmissive member.Thus, good optical distribution can be obtained in the far-field, anduniform emission can be obtained in various directions at the lightemitting surface of the light emitting element. The light transmissivemember preferably has a thickness of at least 10 μm. Further preferablythe thickness is in a range of about 30 ⋅m to 300 ⋅m.

Sixth Embodiment

FIG. 25(a) is a schematic cross-sectional view showing a light emittingdevice according to a sixth embodiment of the present invention.Repeated descriptions as in the fifth embodiment may be omitted.

In the present embodiment, the light emitting device 200A includes alight emitting element 204A having electrodes disposed on thesemiconductor layer 204 b, electrically conductive members 102respectively directly or through the die-bonding member 111 connected tocorresponding electrodes 204 c of the light emitting element 204A, areflective member 114 covering peripheral portions of the electrodes 204c of the light emitting element 204A and the electrically conductivemembers 102, and a light transmissive member 108 covering an uppersurface which is opposite to the surface where the electrodes 204 c aredisposed, and the side surfaces of the light emitting element 204A. Thatis, the construction also includes a light emitting element 204A havinga semiconductor layer 204 b and a transparent substrate 204 a, areflective member 114 applied so that at least a portion of a sidesurface and the upper surface of the transparent substrate 204 a areexposed and a side surface of the semiconductor layer 204A is coveredtherewith, and the light transmissive member 108 which covers theportions exposed from the reflective member 114.

The reflective member 114 covers at least the sides surfaces of theconductive portions such as the electrically conductive members 102 anddie-bonding members 111. In the present embodiment, the reflectivemember 114 further covers the side surfaces of the electrodes 104 c andthe side surfaces of the semiconductor layer 204 b of the light emittingelement 104A. The light transmissive member 108 covers the upper surfaceand the side surfaces of the transparent substrate 204 a of the lightemitting element 204A. The interface between the light transmissivemember 108 and the reflective member 114 is disposed approximately thesame height as or higher than the interface between the semiconductorlayer 204 b and the transparent substrate 204 a. The light propagatingin the semiconductor layer 204 b is emitted through the transparentsubstrate 204 a exposed from the reflective member 114.

As described above, the light emitting device 200A according to thepresent embodiment has the side surfaces of the electrically conductivemembers 102 and the die-bonding members 111 covered with the reflectivemember 114, so that optical loss due to light from the light emittingelement 104A entering the electrically conductive members 102 anddie-bonding members 111 can be reduced. The light propagating downwardlyfrom the light emitting element 204A is reflected by the reflectivemember 114 having high reflectance or the electrode 204 c, thus lightcan be extracted efficiently. Also, in the present embodiment, thereflective member 114 is formed to a height that covers the sidesurfaces of the semiconductor layer 204 b, so that the light propagatingdownwardly from the light emitting element 204A can be reduced and thusthe light extraction efficiency can be enhanced.

In the above, there is described the fifth and the sixth embodiments ofthe invention, it is to be understood that the present invention is notlimited thereto but may be variously embodied to practice within thescope of the present invention. For example, the reflective member maydirectly cover the side surfaces of the light emitting element, but inthe case where an insulating protective film is applied on the sidesurfaces of the electrodes and the semiconductor layer of the lightemitting element, the reflective member may indirectly cover the lightemitting element through the protective film.

Also, as shown in FIG. 25(b), the upper surface of the reflective member114 disposed around the light emitting element 304A may be formed asoutwardly decreasing slope or curved surface. The light emitting device300A according to the present variant example has the reflective member114 covering at least the side surfaces of the electrically conductivemembers 102 and die-bonding members 111. The reflective member 114 mayfurther cover the side surfaces of the electrodes 304 c andsemiconductor layer 304 b of the light emitting element. The lighttransmissive member 108 covers the upper surface and side surfaces ofthe transparent substrate 304 a of the light emitting element 304A. Theinterface between the light transmissive member 108 and the reflectivemember 114 is formed with a slope or curved surface which decreases withdistance from the light emitting element 304A. As in the light emittingdevice 300A shown in the variant example described above, arranging theupper surface of the reflective member 114 in a sloped or curved shapeoutwardly from the light emitting device enables to facilitateextraction of light which is reflected at the light transmissive member108 and the wavelength converting member and then goes toward thereflective member 114 side to outside.

Also, in the light emitting element, at the surface side where theelectrodes are formed, the surfaces of the semiconductor layer exposedfrom the electrodes are preferably covered with the reflective member,but as shown in FIG. 26, at least a portion of the surfaces of thesemiconductor layer 404 b exposed from the electrodes 404 c may beexposed from the reflective member 114. In the light emitting device400A of the variant example, the reflective member 114 is formed as athin film covering the side surfaces of the conductive portion such asthe electrically conductive members 102, die-bonding member 111 and theelectrodes 404 c. Forming the reflective member 114 as a thin film asdescribed above, light can be prevented from entering the electricallyconductive members 102 and the die-bonding member 111 with the smallamount of reflective member 114. At the lower surface of the lightemitting device 400A, a thin film of the reflective member 114 ispreferably disposed on the portion where the electrically conductivemembers 102 are not arranged. With this, the light from the lightemitting element 404A can be prevented from leaking out from the lowersurface side of the light emitting device 400A, so that the lightextraction efficiency in an upper surface direction can be improved.

Further, in the specification, the members shown in claims attachedhereto are not specifically limited to members in the embodiments.Unless otherwise indicated, the sizes, materials, shapes and thearrangement relationships of the members described in the embodimentsare given as an example and not as a limitation to the scope of theinvention. The sizes and the arrangement relationships of the members ineach of drawings are occasionally shown exaggerated for ease ofexplanation.

As described above, the present invention includes an embodiment inwhich a base member is employed, and an embodiment in which no basemember is employed. Moreover, for example, in the light emitting deviceof the fifth and the sixth embodiments in which the base member isremoved, the base member may be divided rather than removed. Forexample, as shown in FIGS. 27(a). 27(b), the light emitting device 300Bor 300C may be formed with the substrate 101 a which is the base memberor the Si substrate 101 b which serves as a protective element may beemployed in addition to the construction of the light emitting device300A (see FIG. 25(b)). Examples of the material used for the base member(substrate 101 a, Si substrate 101 b) include, other than a glass epoxysubstrate, a paper phenol, a liquid crystal polymer, a polyimide resin,a BT resin, a Teflon (registered trademark), silicone, alumina, aluminumnitride, silicone nitride, and a LTCC. In addition, as of Si, the basemember may have an active element or a passive element function.Further, as shown in FIGS. 28(a), 28(b), a Si substrate 101 b isemployed as the base member which is made into a tapered substrate byusing anisotropic etching of Si. With the substrate having a trapezoidalshape as shown in FIG. 28(a), the luminous intensity distribution angleof the light emitted from the light emitting device 300D can be widened.Also, employing a reflector-shape as shown in FIG. 28(b) narrows theluminous intensity distribution angle of the light emitted from thelight emitting device 300E, and thus the frontal luminosity can beenhanced, and the amount of light taken into a secondary optical systemcan be increased.

Next, SEM images of the light emitting device 300B are shown in FIG. 32.FIG. 32(b) is a partially-enlarged views of the areas indicated as “a,”in FIG. 32(a). As shown in FIGS. 32(a), 32(b), at least a portion of theside surfaces and the upper surface of the transparent substrate 304 aare exposed, and the side surfaces of the semiconductor layer 304 b arecovered with the reflective member (filler) 114. Here, the images shownabove illustrate the states in which the reflective member 114 is not incontact with the electrode 304 c and the reflective member 114 is formedaround the electrodes 304 c, but a state in which the reflective member114 is in contact with the electrode 304 c may also employed. In theimage, “KT” indicates a fluorescent material.

INDUSTRIAL APPLICABILITY

The light emitting device according to the present invention is capableof efficiently reflecting light from the light emitting element withouta use of a reflective material which may be subjected to corrosion andthus has excellent light extraction efficiency. Also, even in the casewhere a corrosive reflective material such as silver is employed,deterioration of the reflective material can be prevented, so thatexcellent light extraction efficiency can be obtained. The lightemitting devices according to the present invention can be utilized inapplications such as various indicators, lighting apparatus, displays,backlight light sources for liquid crystal displays, and further, imagereading systems in facsimiles, copiers, scanners or the like, andprojector devices.

DENOTATION OF REFERENCE NUMERALS

-   10, 20, 104 a, 204 a, 304 a, 404 a . . . transparent substrate-   11, 21, 104 b, 204 b, 304 b, 404 b . . . semiconductor layer-   13, 23 . . . protective film-   14 . . . p-type electrode-   16 . . . n-type electrode-   22 a . . . reflective layer-   22 b . . . barrier layer-   22 c . . . bonding layer-   24 . . . electrode-   25 a, 25 b . . . pad electrode-   100, 200, 100A, 200A, 300A, 400A . . . light emitting device-   101, 201 . . . base member (support substrate)-   101 a . . . substrate (base member)-   101 b . . . Si substrate (base member)-   102, 102 a, 102 b, 202 a, 202 b, 202 c, 202 d, 302, 402 . . .    electrically conductive member-   103 . . . metal member-   104, 104A, 204A, 304A, 404A . . . light emitting element-   104 c, 204 c, 304 c, 404 c . . . electrode-   105 . . . protective element-   106, 206 . . . wire (conductive wire)-   108 . . . light transmissive member-   118 . . . separation part-   109, 209, 209 a, 209 b, 209 c . . . recess-   110 . . . bonding member for protective element-   111, 203, 303, 403 . . . bonding member (die-bonding member (solder    material))-   112 . . . dicing sheet-   114 . . . reflective member (filler)-   120, 220, 220 a, 220 b, 220 c . . . bottom surface of recess-   123 . . . joining layer-   130, 230, 230 a, 230 b, 230 c . . . side surface of recess-   140, 240 . . . back surface of base member-   207 . . . light blocking member-   G . . . groove-   KT . . . fluorescent material

1. A light emitting device comprising: a light emitting element having asemiconductor layer and a transparent substrate; a reflective memberexposing at least apart of side surfaces and a top surface of thetransparent substrate and covering side surfaces of the semiconductorlayer; and a light transmissive member covering a portion of thetransparent substrate exposed from the reflective member.
 2. The lightemitting device according to claim 1 further comprising a base memberand electrically conductive members disposed on the base member, whereinthe light emitting element is mounted on the electrically conductivemembers, at a surface of the electrically conductive members, at least aportion of which does not have the light emitting element mountedthereon is covered with an insulating filler which is the reflectivemember, and the light transmissive member covers the light emittingelement.
 3. The light emitting device according to claim 2, wherein thebase member has a recess and the electrically conductive members aredisposed on a bottom surface and side surfaces of the recess, and thelight emitting element is mounted on the bottom surface of the recess.4. The light emitting device according to claim 3, wherein the sidesurfaces of the recess has, at a portion abutting on a top edge surfaceof the recess have a region where an electrically conductive member isnot formed.
 5. The light emitting device according to claim 3, whereinthe side surfaces of the recess at a portion abutting on the bottomsurface of the recess have a region where an electrically conductivemember is not formed.
 6. The light emitting device according to claim 3,wherein at a top edge surface side of the recess, side surfaces of therecess have a step, and a side surface of the step has a region where anelectrically conductive member is not formed.
 7. The light emittingdevice according to claim 6, wherein a shortest distance between ahighest surface of bottom surfaces of the step to a surface of the lighttransmissive member is ⅕ or less with respect to the height of therecess.
 8. The light emitting device according to claim 1, wherein thesurface of the light transmissive member has a recessed shape.
 9. Thelight emitting device according to claim 2 or claim 3, wherein thefiller is applied to a thickness of 5 ⋅m or greater.
 10. The lightemitting device according to claim 2 or claim 3, wherein a reflectanceof the filler is 50% or greater to light of an emission wavelength. 11.The light emitting device according to claim 2 or claim 3, wherein thefiller covers a surface of the light emitting element, and a surfacearea of a single light emitting element which is covered with the filleris less than 50% of the entire surface area of the single light emittingelement.
 12. The light emitting device according to claim 2 or claim 3,wherein the electrically conductive members respectively have a positiveelectrode and a negative electrode, the electrodes are disposed spacedapart from each other on the base member, and the filler is appliedcovering at least a portion between the electrodes.
 13. The lightemitting device according to claim 12, wherein the distance between theelectrodes is 200 ⋅m or less.
 14. The light emitting device according toclaim 2 or claim 3, wherein the light emitting element is mounted in aflip-chip mounting manner.
 15. The light emitting device according toclaim 2 or claim 3, wherein a protective element is mounted in the lightemitting device, and 50% or more of the surface area of the protectiveelement is covered with the filler.
 16. The light emitting deviceaccording to claim 2 or claim 3, wherein at least a portion of thefiller is covered with a light blocking member.
 17. The light emittingdevice according to claim 16, wherein the light blocking member covers aside walls of the base member.
 18. The light emitting device accordingto claim 2 or claim 3, wherein the light transmissive member covers thefiller in addition to the light emitting element.
 19. A light emittingdevice comprising: a base member; electrically conductive membersdisposed on the base member; a light emitting element disposed on theelectrically conductive members; a wire electrically connecting eachelectrode portion of the electrically conductive members with respectiveelectrode terminals of the light emitting element; an insulating fillercovering an electrically conductive portion which does not have thelight emitting element mounted thereon and a lower surface of the wires;and a light transmissive member covering the light emitting element andthe filler.
 20. The light emitting device according to claim 2, claim 3,or claim 19, wherein gaps among the filler are impregnated with a lighttransmissive member.
 21. The light emitting device according to claim20, wherein in a region covered with the filler, the filler is containedmore than 50 volume percent with respect to a volume of the impregnatedfiller.
 22. A light emitting device comprising: a light emitting elementhaving a semiconductor layer and a positive electrode and a negativeelectrode respectively disposed on respective surfaces of thesemiconductor layer; electrically conductive members each bonded to thepositive electrode and negative electrode respectively; a reflectivemember covering side surfaces of the positive electrode and negativeelectrode and side surfaces of the electrically conductive members; anda light transmissive member covering an upper surface opposite to therespective surfaces having the electrodes disposed thereon and sidesurfaces of the light emitting element.
 23. The light emitting deviceaccording to claim 22, wherein the reflective member is exposed at aside surface of the light emitting device.
 24. The light emitting deviceaccording to claim 22, wherein interface between the light transmissivemember and the reflective member is located at a side surface side ofthe light emitting element.
 25. The light emitting device according toclaim 22, wherein a thickness from an upper surface of the lightemitting element to an upper surface of the light transmissive member isapproximately the same as a thickness from a side surface of the lightemitting element to a side surface of the light transmissive member. 26.The light emitting device according to claim 22, wherein a thicknessfrom an upper surface of the light emitting element to an upper surfaceof the light transmissive member is smaller than a thickness from a sidesurface of the light emitting element to a side surface of the lighttransmissive member.
 27. The light emitting device according to claim22, wherein the light transmissive member contains a wavelengthconverting member.
 28. A method of manufacturing a light emitting devicecomprising the steps of: bonding electrodes of a plurality of lightemitting elements on a support substrate; and disposing a reflectivemember on the support substrate of at least around the electrodes of thelight emitting elements by using an electrolytic plating technique, anelectrodeposition coating technique, or an electrostatic coatingtechnique.
 29. A method of manufacturing a light emitting devicecomprising the steps of: forming electrically conductive members on abase member which is a support substrate; mounting a light emittingelement on the conductive member by die-bonding; applying an insulatingfiller, which is a reflective member, to cover a portion of a surface ofthe respective electrically conductive members where the light emittingelement is not disposed, by using an electrolytic plating technique, anelectrodeposition technique, or an electrostatic coating technique; andcovering the light emitting element with a light transmissive member.30. The method of manufacturing a light emitting device according toclaim 29 in which the base substrate has a recess, wherein electricallyconductive members are disposed on a bottom surface and a side surfaceof the recess, and a light emitting element is mounted on the bottomsurface of the recess.
 31. The method of manufacturing a light emittingdevice according to claim 29 or claim 30, wherein the filler is appliedto a thickness of 5 ⋅m or greater.
 32. The method of manufacturing alight emitting device according to claim 29 or claim 30, wherein afterthe step of die-bonding the method further comprising a step ofwire-bonding of electrically connecting a respective portion of theelectrically conductive members, which serves as an electrode, and anelectrode terminal of the light emitting element by using a wire; and inthe step of applying a filler, the filler is applied to cover a lowerportion of the wire.
 33. The method of manufacturing a light emittingdevice according to claim 29 or claim 30, further comprising a step ofcovering the filler with a light blocking member.
 34. The method ofmanufacturing a light emitting device according to claim 28 furthercomprising the steps of: disposing a light transmissive member on thereflective member to cover a side surface and an upper surface of thelight emitting element; and dividing the light emitting element intoindividual units comprising removing the support substrate and dividingthe reflective member and light transmissive member.
 35. The method ofmanufacturing a light emitting device according to claim 34, wherein inthe step of disposing the light transmissive member, the lighttransmissive member is impregnated in the reflective member.
 36. Themethod of manufacturing a light emitting device according to claim 34,wherein the light transmissive member preferably contains a wavelengthconverting member.